diff --git a/src/index.d.ts b/src/index.d.ts
index 678fd46..a7f88f1 100644
--- a/src/index.d.ts
+++ b/src/index.d.ts
@@ -52,7 +52,7 @@ export declare function ThemeProvider<
 >(props: T): JSX.Element;
 export declare function useTheme(): DefaultTheme;
 export interface ThemeProp {
-  theme?: DefaultTheme;
+  theme: DefaultTheme;
 }
 interface AsProps {
   as?: ValidComponent;
diff --git a/src/index.js b/src/index.js
index 346ed9a..0f3330b 100644
--- a/src/index.js
+++ b/src/index.js
@@ -23,7 +23,7 @@ export function setup(prefixer, shouldForwardProp = null) {
 const ThemeContext = createContext();
 export function ThemeProvider(props) {
   return createComponent(ThemeContext.Provider, {
-    value: props.theme,
+    value: props.theme || {},
     get children() {
       return props.children;
     }