diff --git a/.github/workflows/sphinx-build.yml b/.github/workflows/sphinx-build.yml
new file mode 100644
index 000000000..c09056f9a
--- /dev/null
+++ b/.github/workflows/sphinx-build.yml
@@ -0,0 +1,35 @@
+---
+name: Sphinx build
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  sphinx-build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v4
+        with:
+          python-version: '3.13'
+          cache: 'pip'  # caching pip dependencies
+      - run: pip install .[release]
+
+      - name: Build HTML
+        run: ./action/build_docs.sh
+
+      - name: Upload artifacts
+        uses: actions/upload-artifact@v1
+        with:
+          name: html-docs
+          path: ./sphinx_output/
+
+      - name: Deploy
+        uses: peaceiris/actions-gh-pages@v3
+        if: github.ref == 'refs/heads/master'
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./sphinx_output
+...
diff --git a/.gitignore b/.gitignore
index c452eb6d3..e8657302f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,4 +6,5 @@ __pycache__/
 *.pyc
 /.vscode/
 /build
+/sphinx_output
 /venv
diff --git a/CHANGES.rst b/CHANGES.rst
index 8f7bbb1b2..d22622939 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -5,6 +5,7 @@ These features will be included in the next release:
 
 Added
 -----
+- Add readthedocs site
 - New exit codes 2 for file not found, 3 for invalid command line arguments, 4 for
   missing dependencies and 123 for unknown failures.
 - Display exit code in parentheses after error message.
diff --git a/action/build_docs.sh b/action/build_docs.sh
new file mode 100755
index 000000000..3088c47f8
--- /dev/null
+++ b/action/build_docs.sh
@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+THEME="sphinx_rtd_theme"
+OUTPUT_DIR="../sphinx_output"
+REPO_DIR=$PWD
+
+mkdir -p ../sphinx_project/source
+pushd ../sphinx_project
+
+pip install $THEME
+
+cat <<EOL > source/conf.py
+project = "README"
+html_theme = "$THEME"
+EOL
+
+cp "../README.rst" ../sphinx_project/source/index.rst
+sphinx-build -b html source $OUTPUT_DIR
+
+popd
+mv ../sphinx_project/$OUTPUT_DIR .
+rm -rf ../sphinx_project
diff --git a/setup.cfg b/setup.cfg
index 4739438df..0cf2c8e44 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -83,6 +83,8 @@ test =
     wheel>=0.21.0
 release =
     darkgray-dev-tools~=0.1.1
+    sphinx
+    sphinx-rtd-theme
 
 [flake8]
 # Line length according to Black rules