diff --git a/.github/workflows/internal-testsuite.yml b/.github/workflows/internal-testsuite.yml
index 008d21b9c7..e66f5474c2 100644
--- a/.github/workflows/internal-testsuite.yml
+++ b/.github/workflows/internal-testsuite.yml
@@ -47,6 +47,7 @@ jobs:
       run: |
         git submodule update --init --checkout tests/integration/tests/curl/repo
         git submodule update --init --checkout tests/integration/tests/json-c/repo
+        git submodule update --init --checkout tests/integration/tests/libgit2/repo
         git submodule update --init --checkout tests/integration/tests/lua/repo
         git submodule update --init --checkout tests/integration/tests/nginx/repo
         git submodule update --init --checkout tests/integration/tests/zstd/repo
@@ -75,6 +76,7 @@ jobs:
         sudo apt-get -qq install    \
             bear                    \
             build-essential         \
+            cmake                   \
             libbrotli-dev           \
             libbz2-dev              \
             libclang-${{ matrix.clang-version }}-dev \
@@ -91,6 +93,7 @@ jobs:
             librtmp-dev             \
             libtool                 \
             libzstd-dev             \
+            pkg-config              \
             rcs                     \
             tcl-dev                 \
             tk-dev                  \
@@ -125,7 +128,7 @@ jobs:
         export PATH=$PWD/target/release:$PWD/c2rust-postprocess:$HOME/.local/bin:$PATH
         echo "PATH=$PATH"
         export C2RUST_DIR=$PWD
-        ./tests/integration/test.py curl json-c lua nginx zstd libxml2 python2 libmcs
+        ./tests/integration/test.py curl json-c libgit2 lua nginx zstd libxml2 python2 libmcs
 
     - uses: actions/upload-artifact@v4
       with:
diff --git a/.gitmodules b/.gitmodules
index 69a39f6358..d13de09b28 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -101,3 +101,8 @@
 	path = tests/integration/tests/libmcs/repo
 	url = https://gitlab.com/gtd-gmbh/libmcs
 	update = none
+[submodule "tests/integration/tests/libgit2"]
+	path = tests/integration/tests/libgit2/repo
+	url = https://github.com/libgit2/libgit2
+	ignore = all
+	update = none
diff --git a/tests/integration/tests/libgit2/cmake.sh b/tests/integration/tests/libgit2/cmake.sh
new file mode 100755
index 0000000000..f231c82ca6
--- /dev/null
+++ b/tests/integration/tests/libgit2/cmake.sh
@@ -0,0 +1,33 @@
+#!/bin/bash
+set -e; set -o pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0" )" && pwd)"
+LOG_FILE="$(basename "$0")".log
+BUILD_DIR="$SCRIPT_DIR/repo/build"
+
+rm -f compile_commands.json
+
+cmake -S "$SCRIPT_DIR/repo" -B "$BUILD_DIR" \
+    -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
+    -DBUILD_SHARED_LIBS=OFF \
+    -DBUILD_TESTS=ON \
+    -DBUILD_CLI=OFF \
+    -DBUILD_EXAMPLES=OFF \
+    -DBUILD_FUZZERS=OFF \
+    -DUSE_HTTPS=OFF \
+    -DUSE_SSH=OFF \
+    -DUSE_SHA256=builtin \
+    -DUSE_HTTP_PARSER=builtin \
+    -DREGEX_BACKEND=builtin \
+    -DUSE_BUNDLED_ZLIB=ON \
+    -DUSE_NTLMCLIENT=OFF \
+    -DUSE_ICONV=OFF \
+    2>&1 | tee "$LOG_FILE"
+
+# The test runner expects compile_commands.json in the fixture directory.
+ln -sf repo/build/compile_commands.json compile_commands.json
+
+# clar generates `clar_suite.h` at build time, so the test sources can't be
+# transpiled until the test target is built.
+cmake --build "$BUILD_DIR" --target libgit2_tests --parallel "$(nproc)" \
+    2>&1 | tee -a "$LOG_FILE"
diff --git a/tests/integration/tests/libgit2/conf.yml b/tests/integration/tests/libgit2/conf.yml
new file mode 100644
index 0000000000..9c2dd420ee
--- /dev/null
+++ b/tests/integration/tests/libgit2/conf.yml
@@ -0,0 +1,34 @@
+requirements:
+  ubuntu:
+    apt:
+      packages:
+        - cmake
+        - pkg-config
+
+transpile:
+  autogen: true
+  binary: main # clar test runner's `main()` lives in tests/clar/main.c
+  tflags: --reorganize-definitions --disable-refactoring
+  # libgit2 builds its tests with GIT_DEPRECATE_HARD but not the library
+  # itself (which implements the deprecated APIs), so the same struct has two
+  # incompatible declarations across TUs (e.g. git_remote_callbacks.update_tips
+  # vs .reserved_update_tips). That breaks the refactor stage's
+  # reorganize_definitions pass, which merges declarations by name. Undefine
+  # the macro during transpilation so every TU sees one consistent view; the
+  # structs are layout-identical and the tests don't use deprecated APIs.
+  cflags: -UGIT_DEPRECATE_HARD
+
+cargo.transpile:
+  autogen: true
+
+refactor:
+  autogen: true
+  transforms:
+    - rename_unnamed
+    - reorganize_definitions
+    - shorten_imported_paths
+    - remove_unused_labels
+    - remove_literal_suffixes
+
+cargo.refactor:
+  autogen: true
diff --git a/tests/integration/tests/libgit2/repo b/tests/integration/tests/libgit2/repo
new file mode 160000
index 0000000000..f7164261c9
--- /dev/null
+++ b/tests/integration/tests/libgit2/repo
@@ -0,0 +1 @@
+Subproject commit f7164261c9bc0a7e0ebf767c584e5192810a8b24
diff --git a/tests/integration/tests/libgit2/test.sh b/tests/integration/tests/libgit2/test.sh
new file mode 100755
index 0000000000..825f30c5c2
--- /dev/null
+++ b/tests/integration/tests/libgit2/test.sh
@@ -0,0 +1,8 @@
+#!/bin/bash
+set -e; set -o pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "$0" )" && pwd)"
+
+(cd "$SCRIPT_DIR/repo" && \
+    cargo run --release 2>&1 \
+    | tee "$SCRIPT_DIR/$(basename "$0")".log)