diff --git a/tools/prepare_python.sh b/tools/prepare_python.sh
index 0b22ae6..2151378 100755
--- a/tools/prepare_python.sh
+++ b/tools/prepare_python.sh
@@ -32,9 +32,14 @@ cp ${INCLUDIR}/trexio.h ${PYDIR}/src
 # fix needed to define HAVE_HDF5 symbol so that Python extension is always compiled with HDF5 (without including config.h)
 # add "#define HAVE_HDF5 1" line after "#include stdint.h" using awk and sed
 export LINE_NO=$(($(awk '/stdint.h/{print NR}' ${PYDIR}/src/trexio.h) + 1))
-sed -i'' -e "$LINE_NO"'i \
-#define HAVE_HDF5 1
-' -- ${PYDIR}/src/trexio.h 
+# sed on MacOS is different from GNU sed on Linux and requires special treatment
+if [[ "$OSTYPE" == "darwin"* ]]; then
+  sed -i '' -e "$LINE_NO"'i \
+  #define HAVE_HDF5 1' "${PYDIR}/src/trexio.h"
+else
+  sed -i -e "$LINE_NO"'i \
+  #define HAVE_HDF5 1' "${PYDIR}/src/trexio.h"
+fi
 
 # Copy additional info
 cp ${TREXIO_ROOT}/AUTHORS ${TREXIO_ROOT}/LICENSE ${PYDIR}