diff --git a/docs/Inputs.md b/docs/Inputs.md
index 8a1180bd6d9..5e42f4fb32b 100644
--- a/docs/Inputs.md
+++ b/docs/Inputs.md
@@ -325,8 +325,10 @@ If you need to override the props of the suggestions container (a `Popper` eleme
 
 | Prop | Required | Type | Default | Description |
 | ---|---|---|---|--- |
+| `allowEmpty` | Optional | `boolean` | `false` | If `true`, the first option is an empty one |
+| `allowDuplicates` | Optional | `boolean` | `false` | If `true`, the options can be selected several times |
 | `choices` | Required | `Object[]` | - | List of items to autosuggest |
-| `matchSuggestion` | Optional | `Function` | - | Required if `optionText` is a React element. Function returning a boolean indicating whether a choice matches the filter. `(filter, choice) => boolean`
+| `matchSuggestion` | Optional | `Function` | - | Required if `optionText` is a React element. Function returning a boolean indicating whether a choice matches the filter. `(filter, choice) => boolean` |
 | `optionValue` | Optional | `string` | `id` | Fieldname of record containing the value to use as input value  |
 | `optionText` | Optional | <code>string &#124; Function</code> | `name` | Fieldname of record to display in the suggestion item or function which accepts the current record as argument (`(record)=> {string}`) |
 | `setFilter` | Optional | `Function` | `null` | A callback to inform the `searchText` has changed and new `choices` can be retrieved based on this `searchText`. Signature `searchText => void`. This function is automatically setup when using `ReferenceInput`.  |
diff --git a/packages/ra-core/src/form/useSuggestions.spec.ts b/packages/ra-core/src/form/useSuggestions.spec.ts
index 9a24ec91771..d67d7d2c8f9 100644
--- a/packages/ra-core/src/form/useSuggestions.spec.ts
+++ b/packages/ra-core/src/form/useSuggestions.spec.ts
@@ -120,4 +120,28 @@ describe('getSuggestions', () => {
         expect(getSuggestions(defaultOptions)(false)).toEqual(choices);
         expect(getSuggestions(defaultOptions)(null)).toEqual(choices);
     });
+
+    it('should return all choices if allowDuplicates is true', () => {
+        expect(
+            getSuggestions({
+                ...defaultOptions,
+                allowDuplicates: true,
+                selectedItem: choices[0],
+            })('')
+        ).toEqual([
+            { id: 1, value: 'one' },
+            { id: 2, value: 'two' },
+            { id: 3, value: 'three' },
+        ]);
+    });
+
+    it('should return all the filtered choices if allowDuplicates is true', () => {
+        expect(
+            getSuggestions({
+                ...defaultOptions,
+                allowDuplicates: true,
+                selectedItem: [choices[0]],
+            })('o')
+        ).toEqual([{ id: 1, value: 'one' }, { id: 2, value: 'two' }]);
+    });
 });
diff --git a/packages/ra-core/src/form/useSuggestions.ts b/packages/ra-core/src/form/useSuggestions.ts
index 52064f98600..791216fa229 100644
--- a/packages/ra-core/src/form/useSuggestions.ts
+++ b/packages/ra-core/src/form/useSuggestions.ts
@@ -6,6 +6,7 @@ import { useTranslate } from '../i18n';
 /*
  * Returns helper functions for suggestions handling.
  *
+ * @param allowDuplicates A boolean indicating whether a suggestion can be added several times
  * @param allowEmpty A boolean indicating whether an empty suggestion should be added
  * @param choices An array of available choices
  * @param emptyText The text to use for the empty suggestion. Defaults to an empty string
@@ -24,6 +25,7 @@ import { useTranslate } from '../i18n';
  * - getSuggestions: A function taking a filter value (string) and returning the matching suggestions
  */
 const useSuggestions = ({
+    allowDuplicates,
     allowEmpty,
     choices,
     emptyText = '',
@@ -45,6 +47,7 @@ const useSuggestions = ({
 
     const getSuggestions = useCallback(
         getSuggestionsFactory({
+            allowDuplicates,
             allowEmpty,
             choices,
             emptyText: translate(emptyText, { _: emptyText }),
@@ -59,6 +62,7 @@ const useSuggestions = ({
             suggestionLimit,
         }),
         [
+            allowDuplicates,
             allowEmpty,
             choices,
             emptyText,
@@ -89,6 +93,7 @@ const escapeRegExp = value =>
 
 interface Options extends UseChoicesOptions {
     choices: any[];
+    allowDuplicates?: boolean;
     allowEmpty?: boolean;
     emptyText?: string;
     emptyValue?: any;
@@ -119,7 +124,7 @@ const defaultMatchSuggestion = getChoiceText => (filter, suggestion) => {
  * Get the suggestions to display after applying a fuzzy search on the available choices
  *
  * @example
- * 
+ *
  * getSuggestions({
  *   choices: [{ id: 1, name: 'admin' }, { id: 2, name: 'publisher' }],
  *   optionText: 'name',
@@ -129,17 +134,17 @@ const defaultMatchSuggestion = getChoiceText => (filter, suggestion) => {
  *
  * // Will return [{ id: 2, name: 'publisher' }]
  * getSuggestions({
-    *   choices: [{ id: 1, name: 'admin' }, { id: 2, name: 'publisher' }],
-    *   optionText: 'name',
-    *   optionValue: 'id',
-    *   getSuggestionText: choice => choice[optionText],
-    * })('pub')
-    *
-    * // Will return [{ id: 2, name: 'publisher' }]
-   
+ *   choices: [{ id: 1, name: 'admin' }, { id: 2, name: 'publisher' }],
+ *   optionText: 'name',
+ *   optionValue: 'id',
+ *   getSuggestionText: choice => choice[optionText],
+ * })('pub')
+ *
+ * // Will return [{ id: 2, name: 'publisher' }]
  */
 export const getSuggestionsFactory = ({
     choices = [],
+    allowDuplicates,
     allowEmpty,
     emptyText,
     emptyValue,
@@ -165,21 +170,25 @@ export const getSuggestionsFactory = ({
                 choice =>
                     getChoiceValue(choice) === getChoiceValue(selectedItem)
             );
-        } else {
+        } else if (!allowDuplicates) {
             // ignore the filter to show more choices
             suggestions = removeAlreadySelectedSuggestions(
                 choices,
                 selectedItem,
                 getChoiceValue
             );
+        } else {
+            suggestions = choices;
         }
     } else {
         suggestions = choices.filter(choice => matchSuggestion(filter, choice));
-        suggestions = removeAlreadySelectedSuggestions(
-            suggestions,
-            selectedItem,
-            getChoiceValue
-        );
+        if (!allowDuplicates) {
+            suggestions = removeAlreadySelectedSuggestions(
+                suggestions,
+                selectedItem,
+                getChoiceValue
+            );
+        }
     }
 
     suggestions = limitSuggestions(suggestions, suggestionLimit);
diff --git a/packages/ra-ui-materialui/src/input/AutocompleteArrayInput.tsx b/packages/ra-ui-materialui/src/input/AutocompleteArrayInput.tsx
index 6276b6beeca..401207267e5 100644
--- a/packages/ra-ui-materialui/src/input/AutocompleteArrayInput.tsx
+++ b/packages/ra-ui-materialui/src/input/AutocompleteArrayInput.tsx
@@ -93,6 +93,7 @@ interface Options {
 const AutocompleteArrayInput: FunctionComponent<
     InputProps<TextFieldProps & Options> & DownshiftProps<any>
 > = ({
+    allowDuplicates,
     allowEmpty,
     classes: classesOverride,
     choices = [],
@@ -178,6 +179,7 @@ const AutocompleteArrayInput: FunctionComponent<
     );
 
     const { getChoiceText, getChoiceValue, getSuggestions } = useSuggestions({
+        allowDuplicates,
         allowEmpty,
         choices,
         emptyText,
@@ -234,13 +236,14 @@ const AutocompleteArrayInput: FunctionComponent<
 
     const handleChange = useCallback(
         (item: any) => {
-            let newSelectedItems = selectedItems.includes(item)
-                ? [...selectedItems]
-                : [...selectedItems, item];
+            let newSelectedItems =
+                !allowDuplicates && selectedItems.includes(item)
+                    ? [...selectedItems]
+                    : [...selectedItems, item];
             setFilterValue('');
             input.onChange(newSelectedItems.map(getChoiceValue));
         },
-        [getChoiceValue, input, selectedItems, setFilterValue]
+        [allowDuplicates, getChoiceValue, input, selectedItems, setFilterValue]
     );
 
     const handleDelete = useCallback(