diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -2,12 +2,13 @@
 file(GLOB CSS_SOURCES "*.css")
 file(GLOB_RECURSE GTK2_SOURCES "gtk2/*")
 
+configure_file(build_theme.sh.cmake ${CMAKE_CURRENT_BINARY_DIR}/build_theme.sh @ONLY)
+
 set(SOURCES
     ${SCSS_SOURCES}
     ${CSS_SOURCES}
     ${GTK2_SOURCES}
     render_assets.py
-    build_theme.sh
 )
 
 function(gen_targets THEME_NAME)
@@ -30,16 +31,16 @@
 
 add_custom_command(
     OUTPUT ${Breeze-Dark_TARGETS}
-    DEPENDS ${SOURCES}
-    COMMAND ./build_theme.sh -c BreezeDark -t "${PROJECT_BINARY_DIR}/Breeze-Dark" -r "${BREEZE_COLOR_INSTALL_ROOT}"
+    DEPENDS ${SOURCES} ${CMAKE_CURRENT_BINARY_DIR}/build_theme.sh
+    COMMAND ${CMAKE_CURRENT_BINARY_DIR}/build_theme.sh -c BreezeDark -t "${PROJECT_BINARY_DIR}/Breeze-Dark" -r "${BREEZE_COLOR_INSTALL_ROOT}"
     WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}/src"
 )
 add_custom_target(Breeze-Dark ALL DEPENDS ${Breeze-Dark_TARGETS})
 
 add_custom_command(
     OUTPUT ${Breeze_TARGETS}
-    DEPENDS ${SOURCES}
-    COMMAND ./build_theme.sh -c Breeze -t "${PROJECT_BINARY_DIR}/Breeze" -r "${BREEZE_COLOR_INSTALL_ROOT}"
+    DEPENDS ${SOURCES} ${CMAKE_CURRENT_BINARY_DIR}/build_theme.sh
+    COMMAND ${CMAKE_CURRENT_BINARY_DIR}/build_theme.sh -c Breeze -t "${PROJECT_BINARY_DIR}/Breeze" -r "${BREEZE_COLOR_INSTALL_ROOT}"
     COMMAND cp gtk-dark-3.18.css "${PROJECT_BINARY_DIR}/Breeze/gtk-3.18/gtk-dark.css"
     COMMAND cp gtk-dark-3.20.css "${PROJECT_BINARY_DIR}/Breeze/gtk-3.20/gtk-dark.css"
     WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}/src"
diff --git a/src/build_theme.sh b/src/build_theme.sh.cmake
rename from src/build_theme.sh
rename to src/build_theme.sh.cmake
--- a/src/build_theme.sh
+++ b/src/build_theme.sh.cmake
@@ -42,7 +42,7 @@
   THEME_BUILD_DIR="$(mktemp -d)"
   create_folders "${THEME_BUILD_DIR}"
   cp -R gtk2/* "${THEME_BUILD_DIR}/gtk-2.0/"
-  python3 render_assets.py -c "$1" -a "${THEME_BUILD_DIR}/assets" \
+  @PYTHON_EXECUTABLE@ render_assets.py -c "$1" -a "${THEME_BUILD_DIR}/assets" \
     -g "${THEME_BUILD_DIR}/gtk-2.0" -G "${THEME_BUILD_DIR}" -b "$4"
   build_sass gtk318/gtk.scss "${THEME_BUILD_DIR}/gtk-3.18/gtk.css" "${THEME_BUILD_DIR}"
   build_sass gtk320/gtk.scss "${THEME_BUILD_DIR}/gtk-3.20/gtk.css" "${THEME_BUILD_DIR}"