diff --git a/.github/workflows/sync_repos.yaml b/.github/workflows/sync_repos.yaml
new file mode 100644
index 000000000000..10a6df8514d7
--- /dev/null
+++ b/.github/workflows/sync_repos.yaml
@@ -0,0 +1,31 @@
+# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+# Exceptions. See /LICENSE for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+name: sync-repos
+
+on:
+  push:
+    branches: [trunk]
+    paths:
+      # Minimize where we run this to changes to the top-level files and
+      # specific trees that we sync to other repositories.
+      - '*'
+      - 'utils/**'
+      # Also run if the action itself is updated.
+      - '.github/workflows/sync_repos.yaml'
+      - 'scripts/sync_repos.sh'
+
+jobs:
+  sync-repos:
+    runs-on: ubuntu-latest
+    steps:
+      # Checkout our main repository.
+      - name: Checkout the main repository
+        uses: actions/checkout@v2
+
+      # Run the sync script.
+      - name: Sync to other repositories
+        env:
+          API_TOKEN_GITHUB: ${{ secrets.SYNC_REPOS_API_TOKEN_GITHUB }}
+        run: ./scripts/sync_repos.sh
diff --git a/scripts/sync_repos.sh b/scripts/sync_repos.sh
new file mode 100755
index 000000000000..dda70f6af6f7
--- /dev/null
+++ b/scripts/sync_repos.sh
@@ -0,0 +1,77 @@
+#!/bin/bash -eux
+#
+# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+# Exceptions. See /LICENSE for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+#
+# Sync directories in the main Carbon repository into dedicated child
+# repositories to better match repository-oriented installing and tooling.
+
+ORIGIN_DIR="$PWD"
+COMMIT_SHA="$(git rev-parse --short $GITHUB_SHA)"
+COMMIT_SUMMARY="Original $(git show -s --pretty=full "$COMMIT_SHA")
+
+$(git diff --summary "${COMMIT_SHA}^!")
+"
+
+# Setup global git configuration.
+GIT_USERNAME="CarbonInfraBot"
+git config --global user.email "carbon-external-infra@google.com"
+git config --global user.name "$GIT_USERNAME"
+
+declare -A MIRRORS
+MIRRORS["utils/vim"]="vim-carbon-lang"
+
+for dir in "${!MIRRORS[@]}"; do
+  SRC_DIR="$dir"
+  DEST_REPO="${MIRRORS[$SRC_DIR]}"
+  DEST_REPO_URL="https://$GIT_USERNAME:$API_TOKEN_GITHUB@github.com/carbon-language/$DEST_REPO.git"
+  DEST_CLONE_DIR="$(mktemp -d)"
+
+  git clone --single-branch "$DEST_REPO_URL" "$DEST_CLONE_DIR"
+  cd "$DEST_CLONE_DIR"
+
+  # Print out the destination repository to help with debugging failures in
+  # GitHub's actions.
+  ls -al
+
+  # Remove all the existing files to rebuild it from scratch. We ignore when
+  # this matches no files to handle freshly created repositories. Also print the
+  # status afterward for debugging.
+  git rm --ignore-unmatch -r .
+  git status
+
+  # Copy the basic framework from the origin repository.
+  cp "$ORIGIN_DIR/.gitignore" \
+    "$ORIGIN_DIR/CODE_OF_CONDUCT.md" \
+    "$ORIGIN_DIR/LICENSE" \
+    .
+
+  # Copy the mirrored directory. We use `rsync` to get a more reliable way of
+  # handling the mirroring of the contents of a directory. We also make this
+  # verbose to help with debugging action failures on GitHub.
+  rsync -av "$ORIGIN_DIR/$SRC_DIR/" .
+
+  # Add back all the files now, and print the status for debugging.
+  git add -A
+  git status
+
+  # See if there is anything to commit and push. This works the same way as
+  # diff(1) and so exits zero when there are no changes.
+  if ! git diff --cached --quiet; then
+    # Commit the new state.
+    git commit -F- <<EOF
+Sync $DEST_REPO to carbon-language/carbon-lang@$COMMIT_SHA
+
+$COMMIT_SUMMARY
+EOF
+    git log
+
+    # Push the new commit.
+    git push
+  fi
+
+  # Cleanup.
+  cd "$ORIGIN_DIR"
+  rm -rf "$DEST_CLONE_DIR"
+done
diff --git a/utils/vim/README.md b/utils/vim/README.md
index 5e047c6899b5..e023ead0987c 100644
--- a/utils/vim/README.md
+++ b/utils/vim/README.md
@@ -6,8 +6,20 @@ Exceptions. See /LICENSE for license information.
 SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 -->
 
-For Carbon devs using Vim or Neovim, this plugin provides syntax highlighting
-for .carbon files found throughout `explorer/testdata`
+For Carbon developers using Vim or Neovim, this plugin provides syntax
+highlighting for .carbon files found throughout `explorer/testdata`
+
+## Repository and contributing
+
+This code is developed as
+[part](https://github.com/carbon-language/carbon-lang/tree/trunk/utils/vim) of
+the [Carbon Language](https://github.com/carbon-language/carbon-lang) project.
+Everything is then automatically mirrored into a dedicated
+[repository](https://github.com/carbon-language/vim-carbon-lang).
+
+If you would like to contribute, please follow the normal
+[Carbon contributing guide](https://github.com/carbon-language/carbon-lang/blob/trunk/CONTRIBUTING.md)
+and submit pull requests to the main repository.
 
 ## Manual Installation