diff --git a/amaranth/back/verilog.py b/amaranth/back/verilog.py
index ace266c15..c29ddcc52 100644
--- a/amaranth/back/verilog.py
+++ b/amaranth/back/verilog.py
@@ -9,7 +9,7 @@
 
 def _convert_rtlil_text(rtlil_text, *, strip_internal_attrs=False, write_verilog_opts=()):
     # This version requirement needs to be synchronized with the one in pyproject.toml!
-    yosys = find_yosys(lambda ver: ver >= (0, 39, 0, 165))
+    yosys = find_yosys(lambda ver: ver >= (0, 40))
 
     script = []
     script.append(f"read_ilang <<rtlil\n{rtlil_text}\nrtlil")
diff --git a/docs/install.rst b/docs/install.rst
index 6fc53b9db..92085238a 100644
--- a/docs/install.rst
+++ b/docs/install.rst
@@ -21,7 +21,7 @@ System requirements
 ..
    This version requirement needs to be synchronized with the one in pyproject.toml!
 
-.. |yosys-version| replace:: 0.38 (or newer)
+.. |yosys-version| replace:: 0.40 (or newer)
 
 Amaranth HDL requires Python 3.8; it works on CPython_ 3.8 (or newer), and works faster on PyPy3.8_ 7.3.7 (or newer). Installation requires pip_ 23.0 (or newer).
 
diff --git a/pyproject.toml b/pyproject.toml
index 763e1a789..9e25f5010 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -24,7 +24,7 @@ dependencies = [
 # - pyproject.toml: tool.pdm.dev-dependencies.test
 # - amaranth/back/verilog.py: _convert_rtlil_text
 # - docs/install.rst: yosys-version
-builtin-yosys = ["amaranth-yosys>=0.39.0.165.post92"]
+builtin-yosys = ["amaranth-yosys>=0.40"]
 remote-build  = ["paramiko~=2.7"]
 
 [project.scripts]
@@ -65,7 +65,7 @@ source-includes = [
 [tool.pdm.dev-dependencies]
 # This version requirement needs to be synchronized with the one in pyproject.toml above!
 test = [
-  "yowasp-yosys>=0.39.0.165.post92",
+  "yowasp-yosys>=0.40",
   "coverage",
 ]
 docs = [