diff --git a/src/arch/SConscript b/src/arch/SConscript
index 3034dacd0a..017875033f 100644
--- a/src/arch/SConscript
+++ b/src/arch/SConscript
@@ -104,7 +104,8 @@ SCons.Tool.SourceFileScanner.add_scanner('.cc.inc', SCons.Tool.CScanner)
 # output from the ISA description (*.isa) files.
 #
 
-parser_files = Glob('isa_parser/*.py')
+# parsetab.py is a file generated by PLY which we don't want to add as a dep.
+parser_files = Glob('isa_parser/*.py', exclude=['*/parsetab.py'])
 micro_asm_py = File('micro_asm.py')
 
 # import ply here because SCons screws with sys.path when performing actions.