diff --git a/src/cmake/cuda_macros.cmake b/src/cmake/cuda_macros.cmake
index 0ff143d8..b51e33e3 100644
--- a/src/cmake/cuda_macros.cmake
+++ b/src/cmake/cuda_macros.cmake
@@ -126,7 +126,7 @@ function ( LLVM_COMPILE_CUDA llvm_src headers prefix llvm_bc_cpp_generated extra
     MAKE_CUDA_BITCODE (${llvm_src} "" llvm_bc "${extra_clang_args}")
 
     add_custom_command (OUTPUT ${llvm_bc_cpp}
-        COMMAND python "${CMAKE_SOURCE_DIR}/src/liboslexec/serialize-bc.py" ${llvm_bc} ${llvm_bc_cpp} ${prefix}
+        COMMAND python3 "${CMAKE_SOURCE_DIR}/src/liboslexec/serialize-bc.py" ${llvm_bc} ${llvm_bc_cpp} ${prefix}
         MAIN_DEPENDENCY ${llvm_src}
         DEPENDS "${CMAKE_SOURCE_DIR}/src/liboslexec/serialize-bc.py" ${llvm_src} ${headers} ${llvm_bc}
         WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}" )
diff --git a/src/liboslexec/CMakeLists.txt b/src/liboslexec/CMakeLists.txt
index 0a2d3d60..1fd6fcf6 100644
--- a/src/liboslexec/CMakeLists.txt
+++ b/src/liboslexec/CMakeLists.txt
@@ -123,7 +123,7 @@ macro ( LLVM_COMPILE llvm_src srclist )
           -Wno-ignored-attributes -Wno-unknown-attributes
           -O3 -fno-math-errno -S -emit-llvm -o ${llvm_asm} ${llvm_src}
       COMMAND "${LLVM_DIRECTORY}/bin/llvm-as" -f -o ${llvm_bc} ${llvm_asm}
-      COMMAND python "${CMAKE_CURRENT_SOURCE_DIR}/serialize-bc.py" ${llvm_bc} ${llvm_bc_cpp} "osl_llvm_compiled_ops"
+      COMMAND python3 "${CMAKE_CURRENT_SOURCE_DIR}/serialize-bc.py" ${llvm_bc} ${llvm_bc_cpp} "osl_llvm_compiled_ops"
       MAIN_DEPENDENCY ${llvm_src}
       DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/serialize-bc.py"
               ${exec_headers} ${PROJECT_PUBLIC_HEADERS}
@@ -161,7 +161,7 @@ macro ( CUDA_SHADEOPS_COMPILE srclist )
 
     # Serialize the linked bitcode into a CPP file and add it to the list of liboslexec soures
     add_custom_command ( OUTPUT ${shadeops_bc_cuda_cpp}
-        COMMAND python "${CMAKE_CURRENT_SOURCE_DIR}/serialize-bc.py"
+        COMMAND python3 "${CMAKE_CURRENT_SOURCE_DIR}/serialize-bc.py"
             ${linked_shadeops_bc} ${shadeops_bc_cuda_cpp} "osl_llvm_compiled_ops_cuda"
         DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/serialize-bc.py" ${linked_shadeops_bc}
         ${exec_headers} ${PROJECT_PUBLIC_HEADERS}
diff --git a/src/shaders/MaterialX/CMakeLists.txt b/src/shaders/MaterialX/CMakeLists.txt
index 8273888e..23d7940d 100644
--- a/src/shaders/MaterialX/CMakeLists.txt
+++ b/src/shaders/MaterialX/CMakeLists.txt
@@ -68,7 +68,7 @@ macro (mx_oslc_compile)
         # message (STATUS "oslc will make ${mxfile_justname} -> ${oslfile_justname} -> ${osofile_justname}")
     endif ()
     add_custom_command (OUTPUT ${osofile}
-        COMMAND python "${CMAKE_CURRENT_SOURCE_DIR}/build_materialX_osl.py"
+        COMMAND python3 "${CMAKE_CURRENT_SOURCE_DIR}/build_materialX_osl.py"
                        -s "${_shader_SHADERNAME}"
                        -m "${mxfile}"
                        -o "${oslfile}"