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}"