diff --git a/Components/6850/6850.cpp b/Components/6850/6850.cpp
index dfc71a61b..0c486a169 100644
--- a/Components/6850/6850.cpp
+++ b/Components/6850/6850.cpp
@@ -8,6 +8,8 @@
 
 #include "6850.hpp"
 
+#include <cassert>
+
 using namespace Motorola::ACIA;
 
 const HalfCycles ACIA::SameAsTransmit;