diff --git a/packages/autocomplete-core/src/__tests__/autocomplete.test.ts b/packages/autocomplete-core/src/__tests__/getAutocompleteSetters.test.ts
similarity index 64%
rename from packages/autocomplete-core/src/__tests__/autocomplete.test.ts
rename to packages/autocomplete-core/src/__tests__/getAutocompleteSetters.test.ts
index 8bc3d777d..4fa93af14 100644
--- a/packages/autocomplete-core/src/__tests__/autocomplete.test.ts
+++ b/packages/autocomplete-core/src/__tests__/getAutocompleteSetters.test.ts
@@ -1,6 +1,8 @@
-import { createAutocomplete } from '..';
+import { createAutocomplete, AutocompleteSuggestion } from '..';
 
-function createSuggestion(items = []) {
+function createSuggestion<TItem extends { label: string }>(
+  items: TItem[] | TItem[][] = []
+): AutocompleteSuggestion<TItem | TItem[]> | AutocompleteSuggestion<TItem[]> {
   return {
     source: {
       getInputValue: ({ suggestion }) => suggestion.label,
@@ -57,22 +59,56 @@ describe('createAutocomplete', () => {
     );
   });
 
-  test('setSuggestions', () => {
-    const onStateChange = jest.fn();
-    const { setSuggestions } = createAutocomplete({
-      getSources: () => [],
-      onStateChange,
+  describe('setSuggestions', () => {
+    test('default', () => {
+      const onStateChange = jest.fn();
+      const { setSuggestions } = createAutocomplete({
+        getSources: () => [],
+        onStateChange,
+      });
+
+      setSuggestions([createSuggestion([{ label: 'hi' }])]);
+
+      expect(onStateChange).toHaveBeenCalledTimes(1);
+      expect(onStateChange).toHaveBeenCalledWith({
+        prevState: expect.any(Object),
+        state: expect.objectContaining({
+          suggestions: [
+            {
+              items: [
+                {
+                  label: 'hi',
+                  __autocomplete_id: 0,
+                },
+              ],
+              source: expect.any(Object),
+            },
+          ],
+        }),
+      });
     });
-    const suggestions = [createSuggestion()];
 
-    setSuggestions(suggestions);
+    test('flattens suggestions', () => {
+      const onStateChange = jest.fn();
+      const { setSuggestions } = createAutocomplete({
+        openOnFocus: true,
+        getSources: () => [],
+        onStateChange,
+      });
 
-    expect(onStateChange).toHaveBeenCalledTimes(1);
-    expect(onStateChange).toHaveBeenCalledWith(
-      expect.objectContaining({
-        state: expect.objectContaining({ suggestions }),
-      })
-    );
+      setSuggestions([createSuggestion([[{ label: 'hi' }]])]);
+
+      expect(onStateChange).toHaveBeenCalledWith({
+        prevState: expect.any(Object),
+        state: expect.objectContaining({
+          suggestions: [
+            expect.objectContaining({
+              items: [{ label: 'hi', __autocomplete_id: 0 }],
+            }),
+          ],
+        }),
+      });
+    });
   });
 
   test('setIsOpen', () => {
diff --git a/packages/autocomplete-core/src/__tests__/utils.test.ts b/packages/autocomplete-core/src/__tests__/utils.test.ts
new file mode 100644
index 000000000..dbac409c6
--- /dev/null
+++ b/packages/autocomplete-core/src/__tests__/utils.test.ts
@@ -0,0 +1,15 @@
+import { flatten } from '../utils';
+
+describe('flatten', () => {
+  it('does not split strings', () => {
+    expect(flatten(['value', 'value'])).toEqual(['value', 'value']);
+  });
+
+  it('spreads arrays', () => {
+    expect(flatten(['value', ['value']])).toEqual(['value', 'value']);
+  });
+
+  it('ignores empty arrays', () => {
+    expect(flatten([[], 'value', 'value'])).toEqual(['value', 'value']);
+  });
+});
diff --git a/packages/autocomplete-core/src/getAutocompleteSetters.ts b/packages/autocomplete-core/src/getAutocompleteSetters.ts
index 780d70ea7..c6d2efe69 100644
--- a/packages/autocomplete-core/src/getAutocompleteSetters.ts
+++ b/packages/autocomplete-core/src/getAutocompleteSetters.ts
@@ -1,4 +1,5 @@
 import { AutocompleteApi, AutocompleteStore } from './types';
+import { flatten } from './utils';
 
 interface GetAutocompleteSettersOptions<TItem> {
   store: AutocompleteStore<TItem>;
@@ -23,7 +24,9 @@ export function getAutocompleteSetters<TItem>({
     let baseItemId = 0;
     const value = rawValue.map((suggestion) => ({
       ...suggestion,
-      items: suggestion.items.map((item) => ({
+      // We flatten the stored items to support calling `getAlgoliaHits`
+      // from the source itself.
+      items: flatten(suggestion.items).map((item) => ({
         ...item,
         __autocomplete_id: baseItemId++,
       })),
diff --git a/packages/autocomplete-core/src/getDefaultProps.ts b/packages/autocomplete-core/src/getDefaultProps.ts
index 5d73722d4..57d9f41e7 100644
--- a/packages/autocomplete-core/src/getDefaultProps.ts
+++ b/packages/autocomplete-core/src/getDefaultProps.ts
@@ -4,6 +4,7 @@ import {
   getItemsCount,
   noop,
   getNormalizedSources,
+  flatten,
 } from './utils';
 
 export function getDefaultProps<TItem>(
@@ -62,11 +63,7 @@ export function getDefaultProps<TItem>(
         )
       )
         .then((nested) =>
-          // same as `nested.flat()`
-          nested.reduce((acc, array) => {
-            acc = acc.concat(array);
-            return acc;
-          }, [])
+          flatten(nested)
         )
         .then((sources) =>
           sources.map((source) => ({
diff --git a/packages/autocomplete-core/src/types/api.ts b/packages/autocomplete-core/src/types/api.ts
index 487e7876d..4b0087fbe 100644
--- a/packages/autocomplete-core/src/types/api.ts
+++ b/packages/autocomplete-core/src/types/api.ts
@@ -93,7 +93,9 @@ export interface AutocompleteSource<TItem> {
   /**
    * Function called when the input changes. You can use this function to filter/search the items based on the query.
    */
-  getSuggestions(params: GetSourcesParams<TItem>): MaybePromise<TItem[]>;
+  getSuggestions(
+    params: GetSourcesParams<TItem>
+  ): MaybePromise<TItem[] | TItem[][]>;
   /**
    * Function called when an item is selected.
    */
diff --git a/packages/autocomplete-core/src/utils.ts b/packages/autocomplete-core/src/utils.ts
index 9a39780fa..1bd98d723 100644
--- a/packages/autocomplete-core/src/utils.ts
+++ b/packages/autocomplete-core/src/utils.ts
@@ -187,3 +187,9 @@ export function getHighlightedItem<TItem>({
 export function isOrContainsNode(parent: Node, child: Node) {
   return parent === child || (parent.contains && parent.contains(child));
 }
+
+export function flatten<TType>(values: Array<TType | TType[]>): TType[] {
+  return values.reduce<TType[]>((a, b) => {
+    return a.concat(b);
+  }, []);
+}