diff --git a/e2e/_api/graphql.mjs b/e2e/_api/graphql.mjs
index f5fd58d758..546e320add 100644
--- a/e2e/_api/graphql.mjs
+++ b/e2e/_api/graphql.mjs
@@ -54,7 +54,7 @@ let cities = [
 ]
 
 // example data
-const data = [
+const _data = [
 	{ id: '1', name: 'Bruce Willis', birthDate: new Date(1955, 2, 19) },
 	{ id: '2', name: 'Samuel Jackson', birthDate: new Date(1948, 11, 21) },
 	{ id: '3', name: 'Morgan Freeman', birthDate: new Date(1937, 5, 0) },
@@ -66,7 +66,7 @@ const data = [
 ]
 const snapshots = {}
 
-function getSnapshot(snapshot) {
+function getSnapshot(snapshot, data = _data) {
 	if (!snapshots[snapshot]) {
 		snapshots[snapshot] = data.map((user) => ({
 			...user,
@@ -88,6 +88,12 @@ async function processFile(file) {
 	})
 }
 
+// example union data
+const unionData = [
+  { __typename: 'ModelA', id: 'm1', data: { x: 1, y: 2 } },
+  { __typename: 'ModelB', id: 'm2', data: { msg: "ok" } },
+]
+
 export const resolvers = {
 	Query: {
 		hello: () => {
@@ -137,7 +143,10 @@ export const resolvers = {
 			}
 			return user
 		},
-		avgYearsBirthDate: () => {
+		modelsConnection(_, args) {
+			return connectionFromArray(getSnapshot(args.snapshot, unionData), args)
+		},
+    avgYearsBirthDate: () => {
 			return list.map((c) => c.birthDate.getFullYear()).reduce((a, b) => a + b) / list.length
 		},
 		node(_, { id: nodeID }) {
diff --git a/e2e/_api/schema.graphql b/e2e/_api/schema.graphql
index 4753c771ab..f870d40bcd 100644
--- a/e2e/_api/schema.graphql
+++ b/e2e/_api/schema.graphql
@@ -58,6 +58,13 @@ type Query {
 	): UserConnection!
 	usersList(limit: Int = 4, offset: Int, snapshot: String!): [User!]!
 	userNodes(limit: Int = 4, offset: Int, snapshot: String!): UserNodes!
+	modelsConnection(
+		after: String
+		before: String
+		first: Int
+		last: Int
+		snapshot: String!
+	): ModelConnection!
 	session: String
 	cities: [City]!
 }
@@ -107,3 +114,32 @@ type City {
 	name: String!
 	libraries: [Library]!
 }
+
+type ModelAData {
+  x: Float!
+  y: Float!
+}
+
+type ModelA {
+  data: ModelAData
+}
+
+type ModelBData {
+  msg: String
+}
+
+type ModelB {
+  data: ModelBData
+}
+
+union Model = ModelA | ModelB
+
+type ModelEdge {
+	cursor: String
+	node: Model
+}
+
+type ModelConnection {
+	edges: [ModelEdge!]!
+	pageInfo: PageInfo!
+}
diff --git a/e2e/sveltekit/src/lib/utils/routes.ts b/e2e/sveltekit/src/lib/utils/routes.ts
index 3bbba8b1fb..d4b042966a 100644
--- a/e2e/sveltekit/src/lib/utils/routes.ts
+++ b/e2e/sveltekit/src/lib/utils/routes.ts
@@ -36,6 +36,7 @@ export const routes = {
   Plugin_query_variable_error: '/plugin/query/variables-error',
   Plugin_query_multiple: '/plugin/query/multiple',
   Plugin_query_scalars: '/plugin/query/scalars',
+  Plugin_query_union: '/plugin/query/union',
   Plugin_query_component: '/plugin/query/component',
   Plugin_query_beforeLoad: '/plugin/query/beforeLoad',
   Plugin_query_afterLoad: '/plugin/query/afterLoad',
diff --git a/e2e/sveltekit/src/routes/plugin/query/union/+page.svelte b/e2e/sveltekit/src/routes/plugin/query/union/+page.svelte
new file mode 100644
index 0000000000..6fbc1335bf
--- /dev/null
+++ b/e2e/sveltekit/src/routes/plugin/query/union/+page.svelte
@@ -0,0 +1,40 @@
+<script>
+  import { graphql } from '$houdini';
+
+  const result = graphql`
+    query PreprocessorTestQueryUnion {
+      modelsConnection(snapshot: "preprocess-query-union") {
+        edges {
+          node {
+            __typename
+            ... on ModelA {
+              data {
+                x
+                y
+              }
+            }
+            ... on ModelB {
+              data {
+                msg
+              }
+            }
+          }
+        }
+      }
+    }
+  `;
+</script>
+
+{#if $result.data?.modelsConnection?.edges}
+  {#each $result.data?.modelsConnection.edges as edge}
+    {#if edge.node.__typename === "ModelA"}
+      <div id="result-union-model-a">
+        x: {edge.node.data?.x}
+      </div>
+    {:else if edge.node.__typename === "ModelB"}
+      <div id="result-union-model-b">
+        msg: {edge.node.data?.msg}
+      </div>
+    {/if}
+  {/each}
+{/if}
diff --git a/e2e/sveltekit/src/routes/plugin/query/union/spec.ts b/e2e/sveltekit/src/routes/plugin/query/union/spec.ts
new file mode 100644
index 0000000000..0e1fe7befe
--- /dev/null
+++ b/e2e/sveltekit/src/routes/plugin/query/union/spec.ts
@@ -0,0 +1,26 @@
+import { routes } from '../../../../lib/utils/routes.js';
+import {
+  expectToBe,
+  goto,
+  navSelector,
+  clientSideNavigation,
+  expect_0_gql
+} from '../../../../lib/utils/testsHelper.js';
+import { test } from '@playwright/test';
+
+test.describe('query preprocessor unions', () => {
+  test('query arrays with unions get unmarshaled into different types', async function ({ page }) {
+    await goto(page, routes.Plugin_query_union);
+    await clientSideNavigation(page, routes.Home);
+
+    // We want the query in the frontend, so we navigate to the page
+    // to zoom on union test & data
+    await expect_0_gql(page, navSelector(routes.Plugin_query_union));
+
+    // Expect first type data to be set
+    await expectToBe(page, 'x: 1', 'div[id=result-union-model-a]');
+
+    // Expect second type data to be set
+    await expectToBe(page, 'msg: ok', 'div[id=result-union-model-b]');
+  });
+});