diff --git a/.changeset/thick-teams-taste.md b/.changeset/thick-teams-taste.md
new file mode 100644
index 00000000000..1e528018f9f
--- /dev/null
+++ b/.changeset/thick-teams-taste.md
@@ -0,0 +1,5 @@
+---
+'@primer/react': minor
+---
+
+Remove the CSS modules feature flag from the TreeView component
diff --git a/packages/react/src/TreeView/TreeView.test.tsx b/packages/react/src/TreeView/TreeView.test.tsx
index 473692e3f98..cb7399ceb84 100644
--- a/packages/react/src/TreeView/TreeView.test.tsx
+++ b/packages/react/src/TreeView/TreeView.test.tsx
@@ -4,7 +4,6 @@ import React from 'react'
 import {ThemeProvider} from '../ThemeProvider'
 import type {SubTreeState} from './TreeView'
 import {TreeView} from './TreeView'
-import {FeatureFlags} from '../FeatureFlags'
 
 jest.useFakeTimers()
 
@@ -1651,20 +1650,8 @@ describe('CSS Module Migration', () => {
         <TreeView.Item id="item-3">Item 3</TreeView.Item>
       </TreeView>
     )
-    const FeatureFlagElement = () => {
-      return (
-        <FeatureFlags
-          flags={{
-            primer_react_css_modules_ga: true,
-          }}
-        >
-          <TreeViewTestComponent />
-        </FeatureFlags>
-      )
-    }
 
     // Testing on the second child element because the first child element is visually hidden
     expect(render(<TreeViewTestComponent />).container.children[1]).toHaveClass('test-class-name')
-    expect(render(<FeatureFlagElement />).container.children[1]).toHaveClass('test-class-name')
   })
 })
diff --git a/packages/react/src/TreeView/TreeView.tsx b/packages/react/src/TreeView/TreeView.tsx
index 95e6e11bb20..ce07a66683d 100644
--- a/packages/react/src/TreeView/TreeView.tsx
+++ b/packages/react/src/TreeView/TreeView.tsx
@@ -6,28 +6,20 @@ import {
 } from '@primer/octicons-react'
 import {clsx} from 'clsx'
 import React, {useCallback, useEffect} from 'react'
-import styled from 'styled-components'
 import classes from './TreeView.module.css'
 import {ConfirmationDialog} from '../ConfirmationDialog/ConfirmationDialog'
 import Spinner from '../Spinner'
 import Text from '../Text'
 import VisuallyHidden from '../_VisuallyHidden'
-import {get} from '../constants'
 import {useControllableState} from '../hooks/useControllableState'
 import {useId} from '../hooks/useId'
 import useSafeTimeout from '../hooks/useSafeTimeout'
 import {useSlots} from '../hooks/useSlots'
-import type {SxProp} from '../sx'
-import sx from '../sx'
 import {getAccessibleName} from './shared'
 import {getFirstChildElement, useRovingTabIndex} from './useRovingTabIndex'
 import {useTypeahead} from './useTypeahead'
 import {SkeletonAvatar} from '../experimental/Skeleton/SkeletonAvatar'
 import {SkeletonText} from '../experimental/Skeleton/SkeletonText'
-import {toggleStyledComponent} from '../internal/utils/toggleStyledComponent'
-import {useFeatureFlag} from '../FeatureFlags'
-
-const CSS_MODULES_FEATURE_FLAG = 'primer_react_css_modules_ga'
 
 // ----------------------------------------------------------------------------
 // Context
@@ -79,225 +71,6 @@ export type TreeViewProps = {
 /* Size of toggle icon in pixels. */
 const TOGGLE_ICON_SIZE = 12
 
-const UlBox = toggleStyledComponent(
-  CSS_MODULES_FEATURE_FLAG,
-  'ul',
-  styled.ul<SxProp>`
-    list-style: none;
-    padding: 0;
-    margin: 0;
-
-    /*
-     * WARNING: This is a performance optimization.
-     *
-     * We define styles for the tree items at the root level of the tree
-     * to avoid recomputing the styles for each item when the tree updates.
-     * We're sacraficing maintainability for performance because TreeView
-     * needs to be performant enough to handle large trees (thousands of items).
-     *
-     * This is intended to be a temporary solution until we can improve the
-     * performance of our styling patterns.
-     *
-     * Do NOT copy this pattern without understanding the tradeoffs.
-     * Do NOT reference PRIVATE_* classnames outside of this file.
-     */
-    .PRIVATE_TreeView-item {
-      outline: none;
-
-      &:focus-visible > div,
-      &.focus-visible > div {
-        box-shadow: inset 0 0 0 2px ${get(`colors.accent.fg`)};
-        @media (forced-colors: active) {
-          outline: 2px solid HighlightText;
-          outline-offset: -2;
-        }
-      }
-      &[data-has-leading-action] {
-        --has-leading-action: 1;
-      }
-    }
-
-    .PRIVATE_TreeView-item-container {
-      --level: 1; /* default level */
-      --toggle-width: 1rem; /* 16px */
-      --min-item-height: 2rem; /* 32px */
-      position: relative;
-      display: grid;
-      --leading-action-width: calc(var(--has-leading-action, 0) * 1.5rem);
-      --spacer-width: calc(calc(var(--level) - 1) * (var(--toggle-width) / 2));
-      grid-template-columns: var(--spacer-width) var(--leading-action-width) var(--toggle-width) 1fr;
-      grid-template-areas: 'spacer leadingAction toggle content';
-      width: 100%;
-      font-size: ${get('fontSizes.1')};
-      color: ${get('colors.fg.default')};
-      border-radius: ${get('radii.2')};
-      cursor: pointer;
-
-      &:hover {
-        background-color: ${get('colors.actionListItem.default.hoverBg')};
-
-        @media (forced-colors: active) {
-          outline: 2px solid transparent;
-          outline-offset: -2px;
-        }
-      }
-
-      @media (pointer: coarse) {
-        --toggle-width: 1.5rem; /* 24px */
-        --min-item-height: 2.75rem; /* 44px */
-      }
-
-      &:has(.PRIVATE_TreeView-item-skeleton):hover {
-        background-color: transparent;
-        cursor: default;
-
-        @media (forced-colors: active) {
-          outline: none;
-        }
-      }
-    }
-
-    &[data-omit-spacer='true'] .PRIVATE_TreeView-item-container {
-      grid-template-columns: 0 0 0 1fr;
-    }
-
-    .PRIVATE_TreeView-item[aria-current='true'] > .PRIVATE_TreeView-item-container {
-      background-color: ${get('colors.actionListItem.default.selectedBg')};
-
-      /* Current item indicator */
-      &::after {
-        content: '';
-        position: absolute;
-        top: calc(50% - 0.75rem); /* 50% - 12px */
-        left: -${get('space.2')};
-        width: 0.25rem; /* 4px */
-        height: 1.5rem; /* 24px */
-        background-color: ${get('colors.accent.fg')};
-        border-radius: ${get('radii.2')};
-
-        @media (forced-colors: active) {
-          background-color: HighlightText;
-        }
-      }
-    }
-
-    .PRIVATE_TreeView-item-toggle {
-      grid-area: toggle;
-      display: flex;
-      justify-content: center;
-      align-items: flex-start;
-      /* The toggle should appear vertically centered for single-line items, but remain at the top for items that wrap
-    across more lines. */
-      padding-top: calc(var(--min-item-height) / 2 - ${TOGGLE_ICON_SIZE}px / 2);
-      height: 100%;
-      color: ${get('colors.fg.muted')};
-    }
-
-    .PRIVATE_TreeView-item-toggle--hover:hover {
-      background-color: ${get('colors.treeViewItem.chevron.hoverBg')};
-    }
-
-    .PRIVATE_TreeView-item-toggle--end {
-      border-top-left-radius: ${get('radii.2')};
-      border-bottom-left-radius: ${get('radii.2')};
-    }
-
-    .PRIVATE_TreeView-item-content {
-      grid-area: content;
-      display: flex;
-      height: 100%;
-      padding: 0 ${get('space.2')};
-      gap: ${get('space.2')};
-      line-height: var(--custom-line-height, var(--text-body-lineHeight-medium, 1.4285));
-      /* The dynamic top and bottom padding to maintain the minimum item height for single line items */
-      padding-top: calc((var(--min-item-height) - var(--custom-line-height, 1.3rem)) / 2);
-      padding-bottom: calc((var(--min-item-height) - var(--custom-line-height, 1.3rem)) / 2);
-    }
-
-    .PRIVATE_TreeView-item-content-text {
-      flex: 1 1 auto;
-      width: 0;
-    }
-
-    &[data-truncate-text='true'] .PRIVATE_TreeView-item-content-text {
-      overflow: hidden;
-      white-space: nowrap;
-      text-overflow: ellipsis;
-    }
-
-    &[data-truncate-text='false'] .PRIVATE_TreeView-item-content-text {
-      word-break: break-word;
-    }
-
-    .PRIVATE_TreeView-item-visual {
-      display: flex;
-      align-items: center;
-      color: ${get('colors.fg.muted')};
-      /* The visual icons should appear vertically centered for single-line items, but remain at the top for items that wrap
-    across more lines. */
-      height: var(--custom-line-height, 1.3rem);
-    }
-
-    .PRIVATE_TreeView-item-leading-action {
-      display: flex;
-      color: ${get('colors.fg.muted')};
-      grid-area: leadingAction;
-
-      & > button {
-        flex-shrink: 1;
-      }
-    }
-
-    .PRIVATE_TreeView-item-level-line {
-      width: 100%;
-      height: 100%;
-      border-right: 1px solid;
-
-      /*
-       * On devices without hover, the nesting indicator lines
-       * appear at all times.
-       */
-      border-color: ${get('colors.border.subtle')};
-    }
-
-    /*
-     * On devices with :hover support, the nesting indicator lines
-     * fade in when the user mouses over the entire component,
-     * or when there's focus inside the component. This makes
-     * sure the component remains simple when not in use.
-     */
-    @media (hover: hover) {
-      .PRIVATE_TreeView-item-level-line {
-        border-color: transparent;
-      }
-
-      &:hover .PRIVATE_TreeView-item-level-line,
-      &:focus-within .PRIVATE_TreeView-item-level-line {
-        border-color: ${get('colors.border.subtle')};
-      }
-    }
-
-    .PRIVATE_TreeView-directory-icon {
-      display: grid;
-      color: ${get('colors.treeViewItem.directory.fill')};
-    }
-
-    .PRIVATE_VisuallyHidden {
-      position: absolute;
-      width: 1px;
-      height: 1px;
-      padding: 0;
-      margin: -1px;
-      overflow: hidden;
-      clip: rect(0, 0, 0, 0);
-      white-space: nowrap;
-      border-width: 0;
-    }
-
-    ${sx}
-  `,
-)
-
 const Root: React.FC<TreeViewProps> = ({
   'aria-label': ariaLabel,
   'aria-labelledby': ariaLabelledby,
@@ -344,8 +117,6 @@ const Root: React.FC<TreeViewProps> = ({
     expandedStateCache.current = new Map()
   }
 
-  const cssModulesEnabled = useFeatureFlag(CSS_MODULES_FEATURE_FLAG)
-
   return (
     <RootContext.Provider
       value={{
@@ -357,7 +128,7 @@ const Root: React.FC<TreeViewProps> = ({
         <VisuallyHidden role="status" aria-live="polite" aria-atomic="true">
           {ariaLiveMessage}
         </VisuallyHidden>
-        <UlBox
+        <ul
           ref={containerRef}
           role="tree"
           aria-label={ariaLabel}
@@ -365,11 +136,11 @@ const Root: React.FC<TreeViewProps> = ({
           data-omit-spacer={flat}
           data-truncate-text={truncate || false}
           onMouseDown={onMouseDown}
-          className={clsx(className, {[classes.TreeViewRootUlStyles]: cssModulesEnabled})}
+          className={clsx(className, classes.TreeViewRootUlStyles)}
           style={style}
         >
           {children}
-        </UlBox>
+        </ul>
       </>
     </RootContext.Provider>
   )
@@ -490,8 +261,6 @@ const Item = React.forwardRef<HTMLElement, TreeViewItemProps>(
       slots.trailingVisual ? trailingVisualId : null,
     ].filter(Boolean)
 
-    const cssModulesEnabled = useFeatureFlag(CSS_MODULES_FEATURE_FLAG)
-
     return (
       <ItemContext.Provider
         value={{
@@ -507,7 +276,7 @@ const Item = React.forwardRef<HTMLElement, TreeViewItemProps>(
       >
         {/* @ts-ignore Box doesn't have type support for `ref` used in combination with `as` */}
         <li
-          className={clsx('PRIVATE_TreeView-item', className, {[classes.TreeViewItem]: cssModulesEnabled})}
+          className={clsx('PRIVATE_TreeView-item', className, classes.TreeViewItem)}
           ref={ref as React.ForwardedRef<HTMLLIElement>}
           tabIndex={0}
           id={itemId}
@@ -548,9 +317,7 @@ const Item = React.forwardRef<HTMLElement, TreeViewItemProps>(
           }}
         >
           <div
-            className={clsx('PRIVATE_TreeView-item-container', {
-              [classes.TreeViewItemContainer]: cssModulesEnabled,
-            })}
+            className={clsx('PRIVATE_TreeView-item-container', classes.TreeViewItemContainer)}
             style={{
               // @ts-ignore CSS custom property
               '--level': level,
@@ -573,11 +340,9 @@ const Item = React.forwardRef<HTMLElement, TreeViewItemProps>(
                   'PRIVATE_TreeView-item-toggle',
                   onSelect && 'PRIVATE_TreeView-item-toggle--hover',
                   level === 1 && 'PRIVATE_TreeView-item-toggle--end',
-                  {
-                    [classes.TreeViewItemToggle]: cssModulesEnabled,
-                    [classes.TreeViewItemToggleHover]: cssModulesEnabled,
-                    [classes.TreeViewItemToggleEnd]: cssModulesEnabled,
-                  },
+                  classes.TreeViewItemToggle,
+                  classes.TreeViewItemToggleHover,
+                  classes.TreeViewItemToggleEnd,
                 )}
                 onClick={event => {
                   if (onSelect) {
@@ -592,18 +357,9 @@ const Item = React.forwardRef<HTMLElement, TreeViewItemProps>(
                 )}
               </div>
             ) : null}
-            <div
-              id={labelId}
-              className={clsx('PRIVATE_TreeView-item-content', {
-                [classes.TreeViewItemContent]: cssModulesEnabled,
-              })}
-            >
+            <div id={labelId} className={clsx('PRIVATE_TreeView-item-content', classes.TreeViewItemContent)}>
               {slots.leadingVisual}
-              <span
-                className={clsx('PRIVATE_TreeView-item-content-text', {
-                  [classes.TreeViewItemContentText]: cssModulesEnabled,
-                })}
-              >
+              <span className={clsx('PRIVATE_TreeView-item-content-text', classes.TreeViewItemContentText)}>
                 {childrenWithoutSubTree}
               </span>
               {slots.trailingVisual}
@@ -618,16 +374,10 @@ const Item = React.forwardRef<HTMLElement, TreeViewItemProps>(
 
 /** Lines to indicate the depth of an item in a TreeView */
 const LevelIndicatorLines: React.FC<{level: number}> = ({level}) => {
-  const cssModulesEnabled = useFeatureFlag(CSS_MODULES_FEATURE_FLAG)
   return (
     <div style={{width: '100%', display: 'flex'}}>
       {Array.from({length: level - 1}).map((_, index) => (
-        <div
-          key={index}
-          className={clsx('PRIVATE_TreeView-item-level-line', {
-            [classes.TreeViewItemLevelLine]: cssModulesEnabled,
-          })}
-        />
+        <div key={index} className={clsx('PRIVATE_TreeView-item-level-line', classes.TreeViewItemLevelLine)} />
       ))}
     </div>
   )
@@ -777,66 +527,18 @@ function usePreviousValue<T>(value: T): T {
   return ref.current
 }
 
-const StyledSkeletonItemContainer = toggleStyledComponent(
-  CSS_MODULES_FEATURE_FLAG,
-  'span',
-  styled.span.attrs({
-    className: 'PRIVATE_TreeView-item-skeleton',
-  })`
-    display: flex;
-    align-items: center;
-    column-gap: 0.5rem;
-    height: 2rem;
-
-    @media (pointer: coarse) {
-      height: 2.75rem;
-    }
-
-    &:nth-of-type(5n + 1) {
-      --tree-item-loading-width: 67%;
-    }
-
-    &:nth-of-type(5n + 2) {
-      --tree-item-loading-width: 47%;
-    }
-
-    &:nth-of-type(5n + 3) {
-      --tree-item-loading-width: 73%;
-    }
-
-    &:nth-of-type(5n + 4) {
-      --tree-item-loading-width: 64%;
-    }
-
-    &:nth-of-type(5n + 5) {
-      --tree-item-loading-width: 50%;
-    }
-  `,
-)
-
-const StyledSkeletonText = toggleStyledComponent(
-  CSS_MODULES_FEATURE_FLAG,
-  SkeletonText,
-  styled(SkeletonText)`
-    width: var(--tree-item-loading-width, 67%);
-  `,
-)
-
 const SkeletonItem = () => {
-  const cssModulesEnabled = useFeatureFlag(CSS_MODULES_FEATURE_FLAG)
   return (
-    <StyledSkeletonItemContainer
+    <span
       className={clsx(
-        {
-          [classes.TreeViewSkeletonItemContainerStyle]: cssModulesEnabled,
-          [classes.TreeViewItemSkeleton]: cssModulesEnabled,
-        },
+        classes.TreeViewSkeletonItemContainerStyle,
+        classes.TreeViewItemSkeleton,
         'PRIVATE_TreeView-item-skeleton',
       )}
     >
       <SkeletonAvatar size={16} square />
-      <StyledSkeletonText className={clsx({[classes.TreeItemSkeletonTextStyles]: cssModulesEnabled})} />
-    </StyledSkeletonItemContainer>
+      <SkeletonText className={classes.TreeItemSkeletonTextStyles} />
+    </span>
   )
 }
 
@@ -846,7 +548,6 @@ type LoadingItemProps = {
 
 const LoadingItem = React.forwardRef<HTMLElement, LoadingItemProps>(({count}, ref) => {
   const itemId = useId()
-  const cssModulesEnabled = useFeatureFlag(CSS_MODULES_FEATURE_FLAG)
 
   if (count) {
     return (
@@ -854,9 +555,7 @@ const LoadingItem = React.forwardRef<HTMLElement, LoadingItemProps>(({count}, re
         {Array.from({length: count}).map((_, i) => {
           return <SkeletonItem aria-hidden={true} key={i} />
         })}
-        <div className={clsx('PRIVATE_VisuallyHidden', {[classes.TreeViewVisuallyHidden]: cssModulesEnabled})}>
-          Loading {count} items
-        </div>
+        <div className={clsx('PRIVATE_VisuallyHidden', classes.TreeViewVisuallyHidden)}>Loading {count} items</div>
       </Item>
     )
   }
@@ -908,22 +607,18 @@ export type TreeViewVisualProps = {
 }
 
 const LeadingVisual: React.FC<TreeViewVisualProps> = props => {
-  const cssModulesEnabled = useFeatureFlag(CSS_MODULES_FEATURE_FLAG)
   const {isExpanded, leadingVisualId} = React.useContext(ItemContext)
   const children = typeof props.children === 'function' ? props.children({isExpanded}) : props.children
   return (
     <>
       <div
-        className={clsx('PRIVATE_VisuallyHidden', {[classes.TreeViewVisuallyHidden]: cssModulesEnabled})}
+        className={clsx('PRIVATE_VisuallyHidden', classes.TreeViewVisuallyHidden)}
         aria-hidden={true}
         id={leadingVisualId}
       >
         {props.label}
       </div>
-      <div
-        className={clsx('PRIVATE_TreeView-item-visual', {[classes.TreeViewItemVisual]: cssModulesEnabled})}
-        aria-hidden={true}
-      >
+      <div className={clsx('PRIVATE_TreeView-item-visual', classes.TreeViewItemVisual)} aria-hidden={true}>
         {children}
       </div>
     </>
@@ -933,22 +628,18 @@ const LeadingVisual: React.FC<TreeViewVisualProps> = props => {
 LeadingVisual.displayName = 'TreeView.LeadingVisual'
 
 const TrailingVisual: React.FC<TreeViewVisualProps> = props => {
-  const cssModulesEnabled = useFeatureFlag(CSS_MODULES_FEATURE_FLAG)
   const {isExpanded, trailingVisualId} = React.useContext(ItemContext)
   const children = typeof props.children === 'function' ? props.children({isExpanded}) : props.children
   return (
     <>
       <div
-        className={clsx('PRIVATE_VisuallyHidden', {[classes.TreeViewVisuallyHidden]: cssModulesEnabled})}
+        className={clsx('PRIVATE_VisuallyHidden', classes.TreeViewVisuallyHidden)}
         aria-hidden={true}
         id={trailingVisualId}
       >
         {props.label}
       </div>
-      <div
-        className={clsx('PRIVATE_TreeView-item-visual', {[classes.TreeViewItemVisual]: cssModulesEnabled})}
-        aria-hidden={true}
-      >
+      <div className={clsx('PRIVATE_TreeView-item-visual', classes.TreeViewItemVisual)} aria-hidden={true}>
         {children}
       </div>
     </>
@@ -961,21 +652,15 @@ TrailingVisual.displayName = 'TreeView.TrailingVisual'
 // TreeView.LeadingAction
 
 const LeadingAction: React.FC<TreeViewVisualProps> = props => {
-  const cssModulesEnabled = useFeatureFlag(CSS_MODULES_FEATURE_FLAG)
   const {isExpanded} = React.useContext(ItemContext)
   const children = typeof props.children === 'function' ? props.children({isExpanded}) : props.children
   return (
     <>
-      <div
-        className={clsx('PRIVATE_VisuallyHidden', {[classes.TreeViewVisuallyHidden]: cssModulesEnabled})}
-        aria-hidden={true}
-      >
+      <div className={clsx('PRIVATE_VisuallyHidden', classes.TreeViewVisuallyHidden)} aria-hidden={true}>
         {props.label}
       </div>
       <div
-        className={clsx('PRIVATE_TreeView-item-leading-action', {
-          [classes.TreeViewItemLeadingAction]: cssModulesEnabled,
-        })}
+        className={clsx('PRIVATE_TreeView-item-leading-action', classes.TreeViewItemLeadingAction)}
         aria-hidden={true}
       >
         {children}
@@ -989,11 +674,10 @@ LeadingAction.displayName = 'TreeView.LeadingAction'
 // TreeView.DirectoryIcon
 
 const DirectoryIcon = () => {
-  const cssModulesEnabled = useFeatureFlag(CSS_MODULES_FEATURE_FLAG)
   const {isExpanded} = React.useContext(ItemContext)
   const Icon = isExpanded ? FileDirectoryOpenFillIcon : FileDirectoryFillIcon
   return (
-    <div className={clsx('PRIVATE_TreeView-directory-icon', {[classes.TreeViewDirectoryIcon]: cssModulesEnabled})}>
+    <div className={clsx('PRIVATE_TreeView-directory-icon', classes.TreeViewDirectoryIcon)}>
       <Icon />
     </div>
   )