diff --git a/stdlib/public/core/Set.swift b/stdlib/public/core/Set.swift
index 6c684caaea977..91a67b3d15f2e 100644
--- a/stdlib/public/core/Set.swift
+++ b/stdlib/public/core/Set.swift
@@ -1223,8 +1223,10 @@ extension Set {
   @inlinable
   public __consuming func intersection(_ other: Set<Element>) -> Set<Element> {
     var newSet = Set<Element>()
-    for member in self {
-      if other.contains(member) {
+    let (smaller, larger) =
+      count < other.count ? (self, other) : (other, self)
+    for member in smaller {
+      if larger.contains(member) {
         newSet.insert(member)
       }
     }