diff --git a/ci/build/build-release.sh b/ci/build/build-release.sh
index 1c040b0a..8f61de42 100755
--- a/ci/build/build-release.sh
+++ b/ci/build/build-release.sh
@@ -69,7 +69,7 @@ EOF
   ) > "$VSCODE_OUT_PATH/product.json"
 
   pushd "$VSCODE_OUT_PATH"
-  yarn --production --ignore-scripts
+  yarn --production --frozen-lockfile --ignore-scripts
   popd
 
   # We clear any native module builds.
diff --git a/ci/build/build-static-release.sh b/ci/build/build-static-release.sh
index f2e28fa3..a0242971 100755
--- a/ci/build/build-static-release.sh
+++ b/ci/build/build-static-release.sh
@@ -19,7 +19,7 @@ main() {
   rsync "$node_path" "$RELEASE_PATH/lib/node"
 
   cd "$RELEASE_PATH"
-  yarn --production
+  yarn --production --frozen-lockfile
 }
 
 main "$@"
diff --git a/ci/dev/vscode.sh b/ci/dev/vscode.sh
index d9a67795..6c508747 100755
--- a/ci/dev/vscode.sh
+++ b/ci/dev/vscode.sh
@@ -15,7 +15,7 @@ main() {
   (
     cd lib/vscode
     # Install VS Code dependencies.
-    yarn
+    yarn ${CI+--frozen-lockfile}
   )
 }
 
diff --git a/ci/steps/fmt.sh b/ci/steps/fmt.sh
index f7b1bbb8..5e323596 100755
--- a/ci/steps/fmt.sh
+++ b/ci/steps/fmt.sh
@@ -4,7 +4,7 @@ set -euo pipefail
 main() {
   cd "$(dirname "$0")/../.."
 
-  yarn
+  yarn --frozen-lockfile
 
   git submodule update --init
   # We do not `yarn vscode` to make test.sh faster.
diff --git a/ci/steps/lint.sh b/ci/steps/lint.sh
index c58473fb..b493e160 100755
--- a/ci/steps/lint.sh
+++ b/ci/steps/lint.sh
@@ -4,7 +4,7 @@ set -euo pipefail
 main() {
   cd "$(dirname "$0")/../.."
 
-  yarn
+  yarn --frozen-lockfile
 
   git submodule update --init
   # We do not `yarn vscode` to make test.sh faster.
diff --git a/ci/steps/release.sh b/ci/steps/release.sh
index 5c935522..94f1df8a 100755
--- a/ci/steps/release.sh
+++ b/ci/steps/release.sh
@@ -4,7 +4,7 @@ set -euo pipefail
 main() {
   cd "$(dirname "$0")/../.."
 
-  yarn
+  yarn --frozen-lockfile
   yarn vscode
   yarn build
   yarn build:vscode
diff --git a/ci/steps/test.sh b/ci/steps/test.sh
index 73c3520d..801b2adc 100755
--- a/ci/steps/test.sh
+++ b/ci/steps/test.sh
@@ -4,7 +4,7 @@ set -euo pipefail
 main() {
   cd "$(dirname "$0")/../.."
 
-  yarn
+  yarn --frozen-lockfile
 
   git submodule update --init
   # We do not `yarn vscode` to make test.sh faster.