diff --git a/external/external_cosmotool.cmake b/external/external_cosmotool.cmake
index cc982ec..026532b 100644
--- a/external/external_cosmotool.cmake
+++ b/external/external_cosmotool.cmake
@@ -21,6 +21,7 @@ ExternalProject_Add(cosmotool
 	-DNETCDF_LIBRARY=${NETCDF_LIBRARY}
 	-DNETCDFCPP_LIBRARY=${NETCDFCPP_LIBRARY}
   -DENABLE_SHARP=OFF
+  -DBUILD_PYTHON=OFF
   -DBoost_INCLUDE_DIR=${Boost_INCLUDE_DIRS}
   ${CYTHON_OPTION}