diff --git a/dtool/pptempl/Depends.pp b/dtool/pptempl/Depends.pp
index 4e3c55d37a..8454d2523a 100644
--- a/dtool/pptempl/Depends.pp
+++ b/dtool/pptempl/Depends.pp
@@ -81,7 +81,7 @@
 
     // Now compute the source files.
     #define c_sources $[filter %.c,$[get_sources]]
-    #define cxx_sources $[filter-out %_src.cxx,$[filter %.cxx %.cpp,$[get_sources]]]
+    #define cxx_sources $[filter-out %_src.cxx,$[filter %.cxx %.mm %.cpp,$[get_sources]]]
     #define cxx_interrogate_sources
     #if $[PYTHON_MODULE_ONLY]
       #set cxx_interrogate_sources $[cxx_sources]
@@ -93,7 +93,7 @@
 
     // Define what the object files are.
     #foreach file $[c_sources] $[cxx_sources] $[cxx_interrogate_sources] $[yxx_sources] $[lxx_sources]
-      #define $[file]_obj $[patsubst %.c %.cxx %.cpp %.yxx %.lxx,$[ODIR]/$[obj_prefix]%$[OBJ],$[notdir $[file]]]
+      #define $[file]_obj $[patsubst %.c %.cxx %.mm %.cpp %.yxx %.lxx,$[ODIR]/$[obj_prefix]%$[OBJ],$[notdir $[file]]]
       #push 1 $[file]_obj
     #end file
 
diff --git a/dtool/pptempl/Template.unix.pp b/dtool/pptempl/Template.unix.pp
index ec3bc72bd4..d2fb70e577 100644
--- a/dtool/pptempl/Template.unix.pp
+++ b/dtool/pptempl/Template.unix.pp
@@ -71,7 +71,7 @@
   // These are the source files that our dependency cache file will
   // depend on.  If it's an empty list, we won't bother writing rules to
   // freshen the cache file.
-  #define dep_sources $[sort $[filter %.c %.cxx %.yxx %.lxx %.h %.I %.T,$[dep_sources_1]]]
+  #define dep_sources $[sort $[filter %.c %.cxx %.mm %.yxx %.lxx %.h %.I %.T,$[dep_sources_1]]]
 
   // If there is an __init__.py in the directory, then all Python
   // files in the directory just get installed without having to be