diff --git a/MODULE.bazel b/MODULE.bazel
index 5d1a2fe..47d3d12 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -64,3 +64,13 @@
     strip_prefix = "pw_toolchain_bazel",
 )
 
+# Toolchain registration
+# ======================
+# Register Pigweed's C++ toolchains.
+register_toolchains(
+    "@pigweed//pw_toolchain:cc_toolchain_cortex-m0",
+    "@pigweed//pw_toolchain:cc_toolchain_cortex-m33",
+    "@pigweed//pw_toolchain/host_clang:host_cc_toolchain_linux",
+    "@pigweed//pw_toolchain/host_clang:host_cc_toolchain_macos",
+    dev_dependency = True,
+)