diff --git a/src/core/include/mp-units/dimension.h b/src/core/include/mp-units/dimension.h
index 4ca3b28b..6ab680f4 100644
--- a/src/core/include/mp-units/dimension.h
+++ b/src/core/include/mp-units/dimension.h
@@ -29,6 +29,13 @@
 #include <mp-units/bits/symbol_text.h>
 #include <mp-units/bits/text_tools.h>
 
+#ifndef MP_UNITS_IN_MODULE_INTERFACE
+#include <array>
+#include <iterator>
+#include <string>
+#include <string_view>
+#endif
+
 namespace mp_units {
 
 /**
diff --git a/src/core/include/mp-units/unit.h b/src/core/include/mp-units/unit.h
index d6992469..ca63e0b2 100644
--- a/src/core/include/mp-units/unit.h
+++ b/src/core/include/mp-units/unit.h
@@ -38,7 +38,9 @@
 #include <mp-units/bits/unit_concepts.h>
 
 #ifndef MP_UNITS_IN_MODULE_INTERFACE
+#include <array>
 #include <iterator>
+#include <string>
 #include <string_view>
 #endif