diff --git a/hecl/include/hecl/hecl.hpp b/hecl/include/hecl/hecl.hpp
index 98bed126a..94a70addf 100644
--- a/hecl/include/hecl/hecl.hpp
+++ b/hecl/include/hecl/hecl.hpp
@@ -1290,7 +1290,7 @@ constexpr double SBig(double val) noexcept { return val; }
 #endif
 
 template <typename SizeT>
-constexpr void hash_combine_impl(SizeT& seed, SizeT value) {
+constexpr void hash_combine_impl(SizeT& seed, SizeT value) noexcept {
   seed ^= value + 0x9e3779b9 + (seed << 6) + (seed >> 2);
 }