diff --git a/.changeset/old-islands-relax.md b/.changeset/old-islands-relax.md
new file mode 100644
index 000000000..d2ecd8222
--- /dev/null
+++ b/.changeset/old-islands-relax.md
@@ -0,0 +1,5 @@
+---
+"@khanacademy/wonder-blocks-testing": major
+---
+
+When mocking GraphQL, consider explicit undefined values in a request to be equivalent to missing keys in a mock
diff --git a/packages/wonder-blocks-testing/src/gql/__tests__/gql-request-matches-mock.test.ts b/packages/wonder-blocks-testing/src/gql/__tests__/gql-request-matches-mock.test.ts
index a087d741c..a46cc4f7f 100644
--- a/packages/wonder-blocks-testing/src/gql/__tests__/gql-request-matches-mock.test.ts
+++ b/packages/wonder-blocks-testing/src/gql/__tests__/gql-request-matches-mock.test.ts
@@ -45,7 +45,7 @@ describe("#gqlRequestMatchesMock", () => {
         expect(result).toBe(false);
     });
 
-    it.each([{foo: "bar"}, {foo: "baz", anExtra: "property"}, null])(
+    it.each([{foo: undefined}, {foo: "baz", anExtra: "property"}, null])(
         "should return false if variables don't match",
         (variables: any) => {
             // Arrange
@@ -158,6 +158,7 @@ describe("#gqlRequestMatchesMock", () => {
             },
             {
                 foo: "bar",
+                baz: undefined,
             },
             {my: "context"},
         );
diff --git a/packages/wonder-blocks-testing/src/gql/gql-request-matches-mock.ts b/packages/wonder-blocks-testing/src/gql/gql-request-matches-mock.ts
index 03b28f361..76ae3ae13 100644
--- a/packages/wonder-blocks-testing/src/gql/gql-request-matches-mock.ts
+++ b/packages/wonder-blocks-testing/src/gql/gql-request-matches-mock.ts
@@ -1,14 +1,11 @@
 import type {GqlOperation, GqlContext} from "@khanacademy/wonder-blocks-data";
 import type {GqlMockOperation} from "./types";
 
-const safeHasOwnProperty = (obj: any, prop: string): boolean =>
-    Object.prototype.hasOwnProperty.call(obj, prop);
-
 // TODO(somewhatabstract, FEI-4268): use a third-party library to do this and
 // possibly make it also support the jest `jest.objectContaining` type matching
 // to simplify mock declaration (note that it would need to work in regular
 // tests and stories/fixtures).
-const areObjectsEqual = (a: any, b: any): boolean => {
+const areObjectsEquivalent = (a: any, b: any): boolean => {
     if (a === b) {
         return true;
     }
@@ -18,14 +15,18 @@ const areObjectsEqual = (a: any, b: any): boolean => {
     if (typeof a !== "object" || typeof b !== "object") {
         return false;
     }
+
+    // Now, we need to compare the values of the objects.
+    // We can't just compare key sets as we want to consider an explicit
+    // key with an undefined value to be the same as a missing key.
+    // It makes for a nicer API when defining mocks.
     const aKeys = Object.keys(a);
     const bKeys = Object.keys(b);
-    if (aKeys.length !== bKeys.length) {
-        return false;
-    }
-    for (let i = 0; i < aKeys.length; i++) {
-        const key = aKeys[i];
-        if (!safeHasOwnProperty(b, key) || !areObjectsEqual(a[key], b[key])) {
+
+    const allKeys = new Set([...aKeys, ...bKeys]);
+
+    for (const key of allKeys) {
+        if (!areObjectsEquivalent(a[key], b[key])) {
             return false;
         }
     }
@@ -52,7 +53,7 @@ export const gqlRequestMatchesMock = (
     // we just assume it matches everything.
     if (mock.variables != null) {
         // Variables have to match.
-        if (!areObjectsEqual(mock.variables, variables)) {
+        if (!areObjectsEquivalent(mock.variables, variables)) {
             return false;
         }
     }
@@ -61,7 +62,7 @@ export const gqlRequestMatchesMock = (
     // we just assume it matches everything.
     if (mock.context != null) {
         // Context has to match.
-        if (!areObjectsEqual(mock.context, context)) {
+        if (!areObjectsEquivalent(mock.context, context)) {
             return false;
         }
     }