diff --git a/src/txmempool.h b/src/txmempool.h
index d0cb41a078e..7fdf1c5a39a 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -23,7 +23,17 @@
 #include <util/result.h>
 #include <util/feefrac.h>
 
+// This works around a bug in Boost <= 1.80.0 when using Clang >=18.
+// See https://github.com/bitcoin/bitcoin/issues/30751.
+#if defined(__clang__)
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wenum-constexpr-conversion"
+#endif
 #include <boost/multi_index/hashed_index.hpp>
+#if defined(__clang__)
+#pragma clang diagnostic pop
+#endif
+
 #include <boost/multi_index/identity.hpp>
 #include <boost/multi_index/indexed_by.hpp>
 #include <boost/multi_index/ordered_index.hpp>