diff --git a/historic/jam/src/build.jam b/historic/jam/src/build.jam
index 07f98e51b..607b26e76 100644
--- a/historic/jam/src/build.jam
+++ b/historic/jam/src/build.jam
@@ -273,7 +273,7 @@ else
 }
 
 # Debug assertions, or not.
-if ! $(debug)
+if ! $(debug) && ! --noassert in $(ARGV)
 {
     --defs += NDEBUG ;
 }
diff --git a/jam_src/build.jam b/jam_src/build.jam
index 07f98e51b..607b26e76 100644
--- a/jam_src/build.jam
+++ b/jam_src/build.jam
@@ -273,7 +273,7 @@ else
 }
 
 # Debug assertions, or not.
-if ! $(debug)
+if ! $(debug) && ! --noassert in $(ARGV)
 {
     --defs += NDEBUG ;
 }