diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index f6868260b..66b93af03 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -14,7 +14,7 @@ jobs:
         uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: stable
+          toolchain: 1.66
           override: true
           components: rustfmt, clippy
 
@@ -43,7 +43,7 @@ jobs:
         uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: stable
+          toolchain: 1.66
           override: true
           components: rustfmt, clippy
 
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
new file mode 100644
index 000000000..c08d70f5a
--- /dev/null
+++ b/rust-toolchain.toml
@@ -0,0 +1,3 @@
+[toolchain]
+channel = "1.66"
+