diff --git a/lib/utils/client.js b/lib/utils/client.js
index 70bc4a1..14e022f 100644
--- a/lib/utils/client.js
+++ b/lib/utils/client.js
@@ -38,7 +38,13 @@ export const isEqual = (first, second) => {
 
   // Check for Set
   if (first instanceof Set && second instanceof Set) {
-    return first.size === second.size && first.isSubsetOf(second);
+    if (first.size !== second.size) return false;
+
+    // Check if all elements in first are also in second
+    for (const item of first) {
+      if (!second.has(item)) return false;
+    }
+    return true;
   }
 
   if (typeof first === 'object') {
@@ -52,7 +58,7 @@ export const isEqual = (first, second) => {
 
     const keys = Object.keys(first);
     if (keys.length !== Object.keys(second).length) return false;
-    return keys.every(key => isEqual(first[key], second[key]));
+    return keys.every((key) => isEqual(first[key], second[key]));
   }
 
   return false;
diff --git a/tests.js b/tests.js
index 5875aa3..b5a7b81 100644
--- a/tests.js
+++ b/tests.js
@@ -4,7 +4,7 @@ import { Mongo, MongoInternals } from 'meteor/mongo';
 import { MongoID } from 'meteor/mongo-id';
 import { DDP } from 'meteor/ddp-client';
 import { Tracker } from 'meteor/tracker';
-import { merge, extractSubscribeArguments } from './lib/utils/client';
+import { merge, extractSubscribeArguments, isEqual } from './lib/utils/client';
 import { convertFilter, removeValue, trim, matchesFilter, convertObjectId, createProjection } from './lib/utils/server';
 import { createKey } from './lib/utils/shared';
 import { subsCache } from './lib/subs-cache';
@@ -2069,6 +2069,126 @@ if (Meteor.isServer) {
 
     test.equal(_isEqual(lodashMerged, merged), true);
   })
+
+  // Tests for isEqual function with Set compatibility
+  Tinytest.add('isEqual - Set equality - identical sets', function (test) {
+    const set1 = new Set([1, 2, 3]);
+    const set2 = new Set([1, 2, 3]);
+    test.isTrue(isEqual(set1, set2), 'Identical sets should be equal');
+  });
+
+  Tinytest.add('isEqual - Set equality - same elements different order', function (test) {
+      const set1 = new Set([1, 2, 3]);
+      const set2 = new Set([3, 1, 2]);
+      test.isTrue(
+        isEqual(set1, set2),
+        'Sets with same elements in different order should be equal'
+      );
+    }
+  );
+
+  Tinytest.add('isEqual - Set inequality - different sizes', function (test) {
+    const set1 = new Set([1, 2, 3]);
+    const set2 = new Set([1, 2]);
+    test.isFalse(
+      isEqual(set1, set2),
+      'Sets with different sizes should not be equal'
+    );
+  });
+
+  Tinytest.add('isEqual - Set inequality - different elements', function (test) {
+      const set1 = new Set([1, 2, 3]);
+      const set2 = new Set([1, 2, 4]);
+      test.isFalse(
+        isEqual(set1, set2),
+        'Sets with different elements should not be equal'
+      );
+    }
+  );
+
+  Tinytest.add('isEqual - Set equality - empty sets', function (test) {
+    const set1 = new Set();
+    const set2 = new Set();
+    test.isTrue(isEqual(set1, set2), 'Empty sets should be equal');
+  });
+
+  Tinytest.add('isEqual - Set inequality - one empty', function (test) {
+    const set1 = new Set();
+    const set2 = new Set([1, 2, 3]);
+    test.isFalse(
+      isEqual(set1, set2),
+      'Empty set should not equal non-empty set'
+    );
+  });
+
+  Tinytest.add('isEqual - Set equality - with strings', function (test) {
+    const set1 = new Set(['a', 'b', 'c']);
+    const set2 = new Set(['c', 'a', 'b']);
+    test.isTrue(
+      isEqual(set1, set2),
+      'Sets with same string elements should be equal'
+    );
+  });
+
+  Tinytest.add('isEqual - Set equality - with objects', function (test) {
+    const obj1 = { id: 1, name: 'test' };
+    const obj2 = { id: 2, name: 'test2' };
+    const set1 = new Set([obj1, obj2]);
+    const set2 = new Set([obj2, obj1]);
+    test.isTrue(
+      isEqual(set1, set2),
+      'Sets with same object elements should be equal'
+    );
+  });
+
+  Tinytest.add('isEqual - Set inequality - with objects', function (test) {
+    const obj1 = { id: 1, name: 'test' };
+    const obj2 = { id: 2, name: 'test2' };
+    const obj3 = { id: 3, name: 'test3' };
+    const set1 = new Set([obj1, obj2]);
+    const set2 = new Set([obj1, obj3]);
+    test.isFalse(
+      isEqual(set1, set2),
+      'Sets with different object elements should not be equal'
+    );
+  });
+
+  Tinytest.add('isEqual - Set vs non-Set', function (test) {
+    const set1 = new Set([1, 2, 3]);
+    const array1 = [1, 2, 3];
+    test.isFalse(isEqual(set1, array1), 'Set should not equal array');
+  });
+
+  Tinytest.add('isEqual - non-Set vs Set', function (test) {
+    const array1 = [1, 2, 3];
+    const set1 = new Set([1, 2, 3]);
+    test.isFalse(isEqual(array1, set1), 'Array should not equal Set');
+  });
+
+  Tinytest.add('isEqual - Set with duplicate values', function (test) {
+    // Note: Sets don't have duplicates, but testing edge case
+    const set1 = new Set([1, 2, 3]);
+    const set2 = new Set([1, 2, 3, 3]); // This will be the same as [1, 2, 3]
+    test.isTrue(
+      isEqual(set1, set2),
+      'Sets should handle duplicate values correctly'
+    );
+  });
+
+  Tinytest.add('isEqual - Set with undefined and null', function (test) {
+    const set1 = new Set([undefined, null, 0]);
+    const set2 = new Set([null, undefined, 0]);
+    test.isTrue(
+      isEqual(set1, set2),
+      'Sets with undefined and null should be equal'
+    );
+  });
+
+  Tinytest.add('isEqual - Set with NaN', function (test) {
+    const set1 = new Set([NaN, 1, 2]);
+    const set2 = new Set([1, NaN, 2]);
+    test.isTrue(isEqual(set1, set2), 'Sets with NaN should be equal');
+  });
 }
 
 Tinytest.addAsync('subscribe - .once - current user is not removed', async (test) => {