diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
new file mode 100644
index 0000000..b0f1401
--- /dev/null
+++ b/.github/workflows/ci.yaml
@@ -0,0 +1,63 @@
+name: CI
+
+on:
+  push:
+    branches:
+    - master
+  pull_request:
+    branches:
+    - master
+
+jobs:
+  build:
+    name: Build on Linux x86_64
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        intrinsics: ["", ".SSE3", ".AVX", ".AVX2"]
+        type: ["", ".PTHREADS", ".MPI", ".HYBRID", ".QuartetMPI"]
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v4
+
+    - name: Install dependencies
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y file openmpi-bin libopenmpi-dev
+
+    - name: Build
+      run: |
+        set -x
+        if [[ -f Makefile${{ matrix.intrinsics }}${{ matrix.type }}.gcc ]]; then
+          make -j -f Makefile${{ matrix.intrinsics }}${{ matrix.type }}.gcc all
+          file raxmlHPC* | grep x86-64
+        fi
+
+  build-aarch64:
+    name: Build on Linux aarch64
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        intrinsics: ["", ".SSE3"]
+        type: ["", ".PTHREADS", ".MPI", ".HYBRID", ".QuartetMPI"]
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v4
+
+    - name: Build
+      uses: uraimo/run-on-arch-action@v2
+      with:
+        arch: aarch64
+        distro: ubuntu20.04
+        githubToken: ${{ github.token }}
+        dockerRunArgs: |
+          --volume "${PWD}:/raxml"
+        install: |
+          apt-get update -q -y
+          apt-get install -q -y make gcc file openmpi-bin libopenmpi-dev
+        run: |
+          set -x
+          make -j -f Makefile${{ matrix.intrinsics }}${{ matrix.type }}.gcc all
+          file raxmlHPC* | grep aarch64
diff --git a/Makefile.SSE3.QuartetMPI.gcc b/Makefile.SSE3.QuartetMPI.gcc
index 764458d..9e3b5c2 100644
--- a/Makefile.SSE3.QuartetMPI.gcc
+++ b/Makefile.SSE3.QuartetMPI.gcc
@@ -3,7 +3,14 @@
 
 CC = mpicc
 
-CFLAGS = -D__SIM_SSE3  -msse3 -D_GNU_SOURCE -O2 -fomit-frame-pointer -funroll-loops  -D_QUARTET_MPI #-Wall -pedantic -Wunused-parameter -Wredundant-decls  -Wreturn-type  -Wswitch-default -Wunused-value -Wimplicit  -Wimplicit-function-declaration  -Wimplicit-int -Wimport  -Wunused  -Wunused-function  -Wunused-label -Wno-int-to-pointer-cast -Wbad-function-cast  -Wmissing-declarations -Wmissing-prototypes  -Wnested-externs  -Wold-style-definition -Wstrict-prototypes  -Wdeclaration-after-statement -Wpointer-sign -Wextra -Wredundant-decls -Wunused -Wunused-function -Wunused-parameter -Wunused-value  -Wunused-variable -Wformat  -Wformat-nonliteral -Wparentheses -Wsequence-point -Wuninitialized -Wundef -Wbad-function-cast
+ARCH := $(shell uname -m)
+ifeq ($(ARCH), x86_64)
+ARCH_CFLAGS=-msse3
+else ifeq ($(ARCH), aarch64)
+ARCH_CFLAGS=
+endif
+
+CFLAGS = -D__SIM_SSE3 $(ARCH_CFLAGS) -D_GNU_SOURCE -O2 -fomit-frame-pointer -funroll-loops  -D_QUARTET_MPI #-Wall -pedantic -Wunused-parameter -Wredundant-decls  -Wreturn-type  -Wswitch-default -Wunused-value -Wimplicit  -Wimplicit-function-declaration  -Wimplicit-int -Wimport  -Wunused  -Wunused-function  -Wunused-label -Wno-int-to-pointer-cast -Wbad-function-cast  -Wmissing-declarations -Wmissing-prototypes  -Wnested-externs  -Wold-style-definition -Wstrict-prototypes  -Wdeclaration-after-statement -Wpointer-sign -Wextra -Wredundant-decls -Wunused -Wunused-function -Wunused-parameter -Wunused-value  -Wunused-variable -Wformat  -Wformat-nonliteral -Wparentheses -Wsequence-point -Wuninitialized -Wundef -Wbad-function-cast
 
 LIBRARIES = -lm