diff --git a/src/common/system.h b/src/common/system.h
index 40206aaa01..4b6aa42150 100644
--- a/src/common/system.h
+++ b/src/common/system.h
@@ -10,7 +10,6 @@
 #include <config/bitcoin-config.h>
 #endif
 
-#include <compat/assumptions.h>
 #include <compat/compat.h>
 
 #include <set>
diff --git a/src/serialize.h b/src/serialize.h
index e53ff9fa4c..dbec620c64 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -7,7 +7,10 @@
 #define BITCOIN_SERIALIZE_H
 
 #include <attributes.h>
+#include <compat/assumptions.h> // IWYU pragma: keep
 #include <compat/endian.h>
+#include <prevector.h>
+#include <span.h>
 
 #include <algorithm>
 #include <cstdint>
@@ -18,13 +21,9 @@
 #include <memory>
 #include <set>
 #include <string>
-#include <string.h>
 #include <utility>
 #include <vector>
 
-#include <prevector.h>
-#include <span.h>
-
 /**
  * The maximum size of a serialized object in bytes or number of elements
  * (for eg vectors) when the size is encoded as CompactSize.