diff --git a/ci/build/npm-postinstall.sh b/ci/build/npm-postinstall.sh
index 127d6408..74b90478 100755
--- a/ci/build/npm-postinstall.sh
+++ b/ci/build/npm-postinstall.sh
@@ -36,6 +36,13 @@ vscode_yarn() {
   yarn --production --frozen-lockfile
   cd extensions
   yarn --production --frozen-lockfile
+  for ext in */; do
+    ext="${ext%/}"
+    echo "extensions/$ext: installing dependencies"
+    cd "$ext"
+    yarn --production --frozen-lockfile
+    cd "$OLDPWD"
+  done
 }
 
 main "$@"