diff --git a/CHANGELOG.md b/CHANGELOG.md
index edbba2e9..965d1d0e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Support `protoc` on Windows.
+
 ## [1.10.1] - 2022-08-01
 
 - Fix missing include files when installing `protoc` on Linux and macOS.
diff --git a/README.md b/README.md
index a3d0bfc2..1110a931 100644
--- a/README.md
+++ b/README.md
@@ -75,7 +75,7 @@ https://spdx.org/licenses
 | [**mdbook-linkcheck**](https://github.com/Michael-F-Bryan/mdbook-linkcheck) | `$CARGO_HOME/bin` | [GitHub Releases](https://github.com/Michael-F-Bryan/mdbook-linkcheck/releases) | Linux, macOS, Windows | [MIT](https://github.com/Michael-F-Bryan/mdbook-linkcheck/blob/HEAD/LICENSE) |
 | [**mdbook**](https://github.com/rust-lang/mdBook) | `$CARGO_HOME/bin` | [GitHub Releases](https://github.com/rust-lang/mdBook/releases) | Linux, macOS, Windows | [MPL-2.0](https://github.com/rust-lang/mdBook/blob/HEAD/LICENSE) |
 | [**nextest**](https://github.com/nextest-rs/nextest) (alias: `cargo-nextest`) | `$CARGO_HOME/bin` | [GitHub Releases](https://github.com/nextest-rs/nextest/releases) | Linux, macOS, Windows | [Apache-2.0](https://github.com/nextest-rs/nextest/blob/HEAD/LICENSE-APACHE) OR [MIT](https://github.com/nextest-rs/nextest/blob/HEAD/LICENSE-MIT) |
-| [**protoc**](https://github.com/protocolbuffers/protobuf) | `/usr/local/bin` | [GitHub Releases](https://github.com/protocolbuffers/protobuf/releases) | Linux, macOS | [BSD-3-Clause](https://github.com/protocolbuffers/protobuf/blob/HEAD/LICENSE) |
+| [**protoc**](https://github.com/protocolbuffers/protobuf) | `/usr/local/bin` | [GitHub Releases](https://github.com/protocolbuffers/protobuf/releases) | Linux, macOS, Windows | [BSD-3-Clause](https://github.com/protocolbuffers/protobuf/blob/HEAD/LICENSE) |
 | [**shellcheck**](https://www.shellcheck.net) | `/usr/local/bin` | [GitHub Releases](https://github.com/koalaman/shellcheck/releases) | Linux, macOS, Windows | [GPL-3.0-or-later](https://github.com/koalaman/shellcheck/blob/HEAD/LICENSE) |
 | [**shfmt**](https://github.com/mvdan/sh) | `/usr/local/bin` | [GitHub Releases](https://github.com/mvdan/sh/releases) | Linux, macOS, Windows | [BSD-3-Clause](https://github.com/mvdan/sh/blob/HEAD/LICENSE) |
 | [**valgrind**](https://valgrind.org) | `/snap/bin` | [snap](https://snapcraft.io/install/valgrind/ubuntu) | Linux | [GPL-2.0-or-later](https://valgrind.org/docs/manual/license.gpl.html) |
diff --git a/main.sh b/main.sh
index 1dd17551..d4df1673 100755
--- a/main.sh
+++ b/main.sh
@@ -240,10 +240,10 @@ for tool in "${tools[@]}"; do
                 cygwin* | msys*)
                     url="${base_url}-win64.zip"
                     bin_dir="${HOME}/.install-action/bin"
-                    # TODO
-                    include_dir=""
+                    include_dir="${HOME}/.install-action/include"
                     if [[ ! -d "${bin_dir}" ]]; then
                         mkdir -p "${bin_dir}"
+                        mkdir -p "${include_dir}"
                         echo "${bin_dir}" >>"${GITHUB_PATH}"
                         export PATH="${PATH}:${bin_dir}"
                     fi
@@ -257,17 +257,20 @@ for tool in "${tools[@]}"; do
                 retry curl --proto '=https' --tlsv1.2 -fsSL --retry 10 --retry-connrefused "${url}" -o tmp.zip
                 unzip tmp.zip
                 mv "bin/protoc${exe}" "${bin_dir}/"
-                if [[ -n "${include_dir}" ]]; then
-                    mkdir -p "${include_dir}/"
-                    sudo cp -r include/. "${include_dir}/"
-                    ls "${include_dir}/"
+                mkdir -p "${include_dir}/"
+                case "${OSTYPE}" in
+                    linux* | darwin*) sudo cp -r include/. "${include_dir}/" ;;
+                    cygwin* | msys*)
+                        cp -r include/. "${include_dir}/"
+                        bin_dir=$(sed <<<"${bin_dir}" 's/^\/c\//C:\\/')
+                        ;;
+                esac
+                if [[ -z "${PROTOC:-}" ]]; then
+                    info "setting PROTOC environment variable"
+                    echo "PROTOC=${bin_dir}/protoc${exe}" >>"${GITHUB_ENV}"
                 fi
             )
             rm -rf .install-action-tmp
-            if [[ -z "${PROTOC:-}" ]]; then
-                info "setting PROTOC environment variable"
-                echo "PROTOC=${bin_dir}/protoc${exe}" >>"${GITHUB_ENV}"
-            fi
             ;;
         shellcheck)
             # https://github.com/koalaman/shellcheck/releases