diff --git a/.github/workflows/ubuntu.yml b/.github/workflows/ubuntu.yml
index 7cc1506..f3115b6 100644
--- a/.github/workflows/ubuntu.yml
+++ b/.github/workflows/ubuntu.yml
@@ -73,6 +73,9 @@ jobs:
           - release: noble
             compiler_name: clang
             compiler_version: 20
+          - release: noble
+            compiler_name: clang
+            compiler_version: 21
     runs-on: ${{ matrix.architecture.runner }}
     permissions:
       packages: write
diff --git a/docker/ubuntu/Dockerfile b/docker/ubuntu/Dockerfile
index 8730e05..598c25a 100644
--- a/docker/ubuntu/Dockerfile
+++ b/docker/ubuntu/Dockerfile
@@ -227,11 +227,25 @@ printf "%s\n" \
   "Acquire::AllowInsecureRepositories \"true\";" \
   "Acquire::AllowWeakRepositories \"true\";" \
   | tee /etc/apt/apt.conf.d/99llvm-allow-weak
+
+# Add LLVM repository for versions above 20 because it is not available in the default repo
+if [[ "${CLANG_VERSION}" -gt 20 ]]; then
+  apt-get update
+  apt-get install -y --no-install-recommends lsb-release software-properties-common gnupg
+  wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -
+  DISTRO_CODENAME=$(lsb_release -cs)
+  echo "deb http://apt.llvm.org/${DISTRO_CODENAME}/ llvm-toolchain-${DISTRO_CODENAME}-${CLANG_VERSION} main" \
+    | tee /etc/apt/sources.list.d/llvm.list
+  apt-get clean
+  rm -rf /var/lib/apt/lists/*
+fi
+
 apt-get update
 apt-get install -y --no-install-recommends --allow-unauthenticated \
   clang-${CLANG_VERSION} \
   libclang-rt-${CLANG_VERSION}-dev \
   llvm-${CLANG_VERSION} \
+  clang-tidy-${CLANG_VERSION} \
   gcc \
   g++
 apt-get clean
@@ -245,6 +259,10 @@ update-alternatives \
   --slave /usr/bin/clang++ clang++ /usr/bin/clang++-${CLANG_VERSION}
 update-alternatives \
   --install /usr/bin/llvm-cov llvm-cov /usr/bin/llvm-cov-${CLANG_VERSION} 100
+update-alternatives \
+  --install /usr/bin/clang-tidy clang-tidy /usr/bin/clang-tidy-${CLANG_VERSION} 100
+update-alternatives \
+  --install /usr/bin/run-clang-tidy run-clang-tidy /usr/bin/run-clang-tidy-${CLANG_VERSION} 100
 update-alternatives --auto cc
 update-alternatives --auto c++
 update-alternatives --auto clang