diff --git a/doc/Doxyfile b/doc/Doxyfile
index 753c383a26..be13926c1d 100644
--- a/doc/Doxyfile
+++ b/doc/Doxyfile
@@ -216,7 +216,7 @@ SEPARATE_MEMBER_PAGES  = NO
 # uses this value to replace tabs by spaces in code fragments.
 # Minimum value: 1, maximum value: 16, default value: 4.
 
-TAB_SIZE               = 8
+TAB_SIZE               = 4
 
 # This tag can be used to specify a number of aliases that act as commands in
 # the documentation. An alias has the form: