diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
@@ -98,3 +98,41 @@ jobs:
           files: coverage.lcov
           token: ${{ secrets.CODECOV_TOKEN }}
           verbose: true
+
+  docs:
+    name: 'Build docs'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout source
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+
+      - name: Create micromamba environment
+        uses: mamba-org/setup-micromamba@main
+        with:
+          environment-file: dev-environment.yml
+          cache-environment: true
+
+      - name: Configure CMake
+        run: |
+          cmake -Bbuild -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX
+
+      - name: Build with CMake
+        working-directory: build
+        run: cmake --build . --parallel 8
+
+      - name: Install docs dependencies
+        run: |
+          python -m pip install myst-parser sphinx sphinx-book-theme
+
+      - name: Build docs
+        working-directory: docs
+        run: |
+          make html
+
+      - name: Upload built docs
+        uses: actions/upload-artifact@v6
+        with:
+          name: git2cpp-docs
+          path: docs/_build/html
diff --git a/.gitignore b/.gitignore
@@ -4,3 +4,6 @@ __pycache__/
 compile_commands.json
 serve.log
 test/test-results/
+
+docs/_build/
+docs/created/
diff --git a/.readthedocs.yaml b/.readthedocs.yaml
@@ -0,0 +1,21 @@
+version: 2
+
+build:
+  os: ubuntu-24.04
+  tools:
+    python: mambaforge-23.11
+  jobs:
+    post_install:
+      - cmake -Bbuild -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX
+      - cd build && make
+      - python -m pip install myst-parser sphinx sphinx-book-theme
+    pre_build:
+      - cd docs && python create_markdown.py
+
+conda:
+  environment: dev-environment.yml
+
+sphinx:
+  builder: html
+  configuration: docs/conf.py
+  fail_on_warning: true
diff --git a/README.md b/README.md
@@ -38,3 +38,22 @@ See the `README.md` in the `wasm` directory for further details.
 
 The latest `cockle` and JupyterLite `terminal` deployments using `git2cpp` are available at
 [https://quantstack.net/git2cpp](https://quantstack.net/git2cpp)
+
+# Documentation
+
+The project documentation is generated from the `git2cpp` help pages. To build the documentation
+locally first build `git2cpp` as usual as described above, then install the documentation
+dependencies:
+
+```bash
+micromamba install myst-parser sphinx sphinx-book-theme
+```
+
+and build the documentation:
+
+```bash
+cd docs
+make html
+```
+
+The top-level documentation page will be `docs/_build/html/index.html`
diff --git a/docs/Makefile b/docs/Makefile
@@ -0,0 +1,18 @@
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = .
+BUILDDIR      = _build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	python create_markdown.py
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
diff --git a/docs/conf.py b/docs/conf.py
@@ -0,0 +1,20 @@
+from datetime import date
+
+project = "git2cpp"
+author = "QuantStack"
+copyright = f"2025-{date.today().year}"
+
+extensions = [
+    "myst_parser",
+]
+
+exclude_patterns = ["_build", "Thumbs.db", ".DS_Store"]
+
+html_static_path = []
+html_theme = "sphinx_book_theme"
+html_theme_options = {
+    "github_url": "https://github.com/QuantStack/git2cpp",
+    "home_page_in_toc": True,
+    "show_navbar_depth": 2,
+}
+html_title = "git2cpp documentation"
diff --git a/docs/create_markdown.py b/docs/create_markdown.py
@@ -0,0 +1,85 @@
+import os
+from pathlib import Path
+import re
+import subprocess
+
+
+def get_filename(args):
+    directory = Path("created").joinpath(*args[:-1])
+    filename = args[-1] + ".md"
+    return directory / filename
+
+
+def sanitise_line(line):
+    # Remove trailing whitespace otherwise the markdown parser can insert an extra \n
+    line = line.rstrip()
+
+    # Replace angular brackets with HTML equivalents.
+    line = line.replace(r"&", r"&amp;")
+    line = line.replace(r"<", r"&lt;")
+    line = line.replace(r">", r"&gt;")
+
+    # If there are whitespace characters at the start of the line, replace the first with an &nbsp
+    # so that it is not discarded by the markdown parser used by the parsed-literal directive.
+    line = re.sub(r"^\s", r"&nbsp;", line)
+
+    return line
+
+
+# Process a single subcommand, adding new subcommands found to to_process.
+def process(args, to_process):
+    cmd = args + ["--help"]
+    cmd_string = " ".join(cmd)
+    filename = get_filename(args)
+    filename.parent.mkdir(parents=True, exist_ok=True)
+
+    print(f"Writing '{cmd_string}' to file {filename}")
+    p = subprocess.run(cmd, capture_output=True, text=True, check=True)
+
+    # Write output markdown file, identifying subcommands at the same time to provide
+    # links to the subcommand markdown files.
+    subcommands = []
+    with open(filename, "w") as f:
+        f.write(f"({filename})=\n")  # Target for links.
+        f.write(f"# {' '.join(args)}\n")
+        f.write("\n")
+        f.write("```{parsed-literal}\n")
+
+        in_subcommand_section = False
+        for line in p.stdout.splitlines():
+            if in_subcommand_section:
+                match = re.match(r"^(  )([\w\-_]+)(\s+.*)$", line)
+                if match:
+                    subcommand = match.group(2)
+                    subcommand_filename = get_filename(args + [subcommand])
+                    line = match.group(1) + f"[{subcommand}]({subcommand_filename})" + match.group(3)
+                    subcommands.append(subcommand)
+            elif line.startswith("SUBCOMMANDS:"):
+                in_subcommand_section = True
+
+            f.write(sanitise_line(line) + "\n")
+        f.write("```\n")
+
+        subcommands.sort()
+        to_process.extend(args + [subcommand] for subcommand in subcommands)
+
+        if len(subcommands) > 0:
+            # Hidden table of contents for subcommands of this command/subcommand.
+            f.write("\n")
+            f.write("```{toctree}\n")
+            f.write(":hidden:\n")
+            for subcommand in subcommands:
+                f.write(f"{args[-1]}/{subcommand}\n")
+            f.write("```\n")
+
+
+if __name__ == "__main__":
+    # Modify the PATH so that git2cpp is found by name, as using a full path will cause the help
+    # pages to write that full path.
+    git2cpp_dir = Path(__file__).parent.parent / 'build'
+    os.environ["PATH"] = f'{git2cpp_dir}{os.pathsep}{os.environ["PATH"]}'
+
+    to_process = [["git2cpp"]]
+    while len(to_process) > 0:
+        subcommand = to_process.pop(0)
+        process(subcommand, to_process)
diff --git a/docs/index.md b/docs/index.md
@@ -0,0 +1,17 @@
+# Overview
+
+`git2cpp` is a C++ wrapper of [libgit2](https://libgit2.org/) to provide a command-line interface
+(CLI) to `git` functionality. The intended use is in WebAssembly in-browser terminals (the
+[cockle](https://github.com/jupyterlite/cockle) and
+[JupyterLite terminal](https://github.com/jupyterlite/terminal) projects) but it can be compiled and
+used on any POSIX-compliant system.
+
+The Help pages here are generated from the `git2cpp` command and subcommands to show the
+functionality that is currently supported. If there are features missing that you would like to use,
+please create an issue in the [git2cpp github repository](https://github.com/QuantStack/git2cpp).
+
+```{toctree}
+:caption: Help pages
+:hidden:
+created/git2cpp
+```