diff --git a/lldb/lit/lit.cfg b/lldb/lit/lit.cfg
index e18719beaeffd91070d3fe4a807382626276f30a..dd89b45fadec30b6317be5f4c7ff80f0646b0128 100644
--- a/lldb/lit/lit.cfg
+++ b/lldb/lit/lit.cfg
@@ -140,7 +140,9 @@ config.substitutions.append(('%cc', config.cc))
 config.substitutions.append(('%cxx', config.cxx))
 
 config.substitutions.append(('%lldb', lldb))
-config.substitutions.append(('%debugserver', debugserver))
+
+if debugserver is not None:
+    config.substitutions.append(('%debugserver', debugserver))
 
 for pattern in [r"\bFileCheck\b",
                 r"\| \bnot\b"]: