diff --git a/test/etc/host-run-test-jar b/test/etc/host-run-test-jar
index 5d6d16a..f672974 100755
--- a/test/etc/host-run-test-jar
+++ b/test/etc/host-run-test-jar
@@ -30,6 +30,9 @@
             exit 1
         fi
         LIB="$1"
+        if [ `uname` = "Darwin" ]; then
+            LIB=${LIB/%so/dylib}
+        fi
         shift
     elif [ "x$1" = "x--boot" ]; then
         shift
@@ -110,10 +113,16 @@
 fi
 
 if [ "$GDB" = "y" ]; then
-    gdb=gdb
-    gdbargs="--args $exe"
-    # Enable for Emacs "M-x gdb" support. TODO: allow extra gdb arguments on command line.
-    # gdbargs="--annotate=3 $gdbargs"
+    if [ `uname` = "Darwin" ]; then
+        gdb=lldb
+        gdbargs="-- $exe"
+        exe=
+    else
+        gdb=gdb
+        gdbargs="--args $exe"
+        # Enable for Emacs "M-x gdb" support. TODO: allow extra gdb arguments on command line.
+        # gdbargs="--annotate=3 $gdbargs"
+    fi
 fi
 
 if [ "$INTERPRETER" = "y" ]; then