diff --git a/.github/workflows/compare-manuals.sh b/.github/workflows/compare-manuals.sh
new file mode 100755
index 000000000000..b2cc68c7831d
--- /dev/null
+++ b/.github/workflows/compare-manuals.sh
@@ -0,0 +1,21 @@
+#!/usr/bin/env nix-shell
+#! nix-shell -i bash -p html-tidy
+
+set -euo pipefail
+shopt -s inherit_errexit
+
+normalize() {
+  tidy \
+      --anchor-as-name no \
+      --coerce-endtags no \
+      --escape-scripts no \
+      --fix-backslash no \
+      --fix-style-tags no \
+      --fix-uri no \
+      --indent yes \
+      --wrap 0 \
+      < "$1" \
+      2> /dev/null
+}
+
+diff -U3 <(normalize "$1") <(normalize "$2")
diff --git a/.github/workflows/manual-rendering.yml b/.github/workflows/manual-rendering.yml
new file mode 100644
index 000000000000..6c4a9507c5ca
--- /dev/null
+++ b/.github/workflows/manual-rendering.yml
@@ -0,0 +1,63 @@
+name: "Check NixOS Manual DocBook rendering against MD rendering"
+
+
+on:
+  schedule:
+    # * is a special character in YAML so you have to quote this string
+    # Check every 24 hours
+    - cron:  '0 0 * * *'
+
+permissions:
+  contents: read
+
+jobs:
+  check-rendering-equivalence:
+    permissions:
+      issues: write  # for peter-evans/create-or-update-comment to create or update comment
+    if: github.repository_owner == 'NixOS'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: cachix/install-nix-action@v17
+        with:
+          # explicitly enable sandbox
+          extra_nix_config: sandbox = true
+      - uses: cachix/cachix-action@v10
+        with:
+          # This cache is for the nixpkgs repo checks and should not be trusted or used elsewhere.
+          name: nixpkgs-ci
+          signingKey: '${{ secrets.CACHIX_SIGNING_KEY }}'
+
+      - name: Build DocBook and MD manuals
+        run: |
+          export NIX_PATH=nixpkgs=$(pwd)
+          nix-build \
+            --option restrict-eval true \
+            -o docbook nixos/release.nix \
+            -A manual.x86_64-linux
+          nix-build \
+            --option restrict-eval true \
+            --arg configuration '{ documentation.nixos.options.allowDocBook = false; }' \
+            -o md nixos/release.nix \
+            -A manual.x86_64-linux
+
+      - name: Compare DocBook and MD manuals
+        id: check
+        run: |
+          .github/workflows/compare-manuals.sh \
+            docbook/share/doc/nixos/options.html \
+            md/share/doc/nixos/options.html
+
+      # if the manual can't be built we don't want to notify anyone.
+      # while this may temporarily hide rendering failures it will be a lot
+      # less noisy until all nixpkgs pull requests have stopped using
+      # docbook for option docs.
+      - name: Comment on failure
+        uses: peter-evans/create-or-update-comment@v2
+        if: ${{ failure() && steps.check.conclusion == 'failure' }}
+        with:
+          issue-number: 189318
+          body: |
+            Markdown and DocBook manuals do not agree.
+
+            Check https://github.com/NixOS/nixpkgs/actions/runs/${{ github.run_id }} for details.