diff --git a/changelog/288.improvement.md b/changelog/288.improvement.md
new file mode 100644
index 000000000..ef345b237
--- /dev/null
+++ b/changelog/288.improvement.md
@@ -0,0 +1,25 @@
+Add the `FormSlotsValidatorAction` abstract class that can be used
+to validate slots which were extracted by a Form.
+
+Example:
+
+```python
+class MyFormValidationAction(FormValidationAction):
+    def name(self) -> Text:
+        return "some_form"
+
+    def validate_slot1(
+        self,
+        slot_value: Any,
+        dispatcher: "CollectingDispatcher",
+        tracker: "Tracker",
+        domain: "DomainDict",
+    ) -> Dict[Text, Any]:
+        if slot_value == "correct_value":
+            return {
+                "slot1": "validated_value",
+            }
+        return {
+            "slot1": None,
+        }
+```
\ No newline at end of file
diff --git a/rasa_sdk/forms.py b/rasa_sdk/forms.py
index 84dac4e73..82df25534 100644
--- a/rasa_sdk/forms.py
+++ b/rasa_sdk/forms.py
@@ -3,6 +3,7 @@
 import warnings
 from typing import Dict, Text, Any, List, Union, Optional, Tuple, cast
 
+from abc import ABC
 from rasa_sdk import utils
 from rasa_sdk.events import SlotSet, EventType, ActiveLoop
 from rasa_sdk.interfaces import Action, ActionExecutionRejection
@@ -691,3 +692,61 @@ def _get_entity_type_of_slot_to_fill(
                 return None
 
         return entity_type
+
+
+class FormValidationAction(Action, ABC):
+    """An action that validates if every extracted slot is valid."""
+
+    async def validate(
+        self,
+        dispatcher: "CollectingDispatcher",
+        tracker: "Tracker",
+        domain: "DomainDict",
+    ) -> List[EventType]:
+        """Validate slots by calling a validation function for each slot.
+
+        Args:
+            dispatcher: the dispatcher which is used to
+                send messages back to the user.
+            tracker: the conversation tracker for the current user.
+            domain: the bot's domain.
+        Returns:
+            `SlotSet` events for every validated slot.
+        """
+        slots: Dict[Text, Any] = tracker.slots_to_validate()
+
+        for slot_name, slot_value in slots.items():
+            function_name = f"validate_{slot_name}"
+            validate_func = getattr(self, function_name, None)
+
+            if not validate_func:
+                warnings.warn(
+                    f"Cannot validate `{slot_name}`: there is no validation function specified."
+                )
+                continue
+
+            if utils.is_coroutine_action(validate_func):
+                validation_output = await validate_func(
+                    slot_value, dispatcher, tracker, domain
+                )
+            else:
+                validation_output = validate_func(
+                    slot_value, dispatcher, tracker, domain
+                )
+
+            if validation_output:
+                slots.update(validation_output)
+            else:
+                warnings.warn(
+                    f"Cannot validate `{slot_name}`: make sure the validation function returns the correct output."
+                )
+
+        return [SlotSet(slot, value) for slot, value in slots.items()]
+
+    async def run(
+        self,
+        dispatcher: "CollectingDispatcher",
+        tracker: "Tracker",
+        domain: "DomainDict",
+    ) -> List[EventType]:
+        return await self.validate(dispatcher, tracker, domain)
diff --git a/tests/test_forms.py b/tests/test_forms.py
index b7a7d15db..6fdf01c11 100644
--- a/tests/test_forms.py
+++ b/tests/test_forms.py
@@ -3,9 +3,15 @@
 from typing import Type, Text, Dict, Any, List, Optional
 
 from rasa_sdk import Tracker, ActionExecutionRejection
+from rasa_sdk.types import DomainDict
 from rasa_sdk.events import SlotSet, ActiveLoop
 from rasa_sdk.executor import CollectingDispatcher
-from rasa_sdk.forms import FormAction, REQUESTED_SLOT, LOOP_INTERRUPTED_KEY
+from rasa_sdk.forms import (
+    FormAction,
+    FormValidationAction,
+    REQUESTED_SLOT,
+    LOOP_INTERRUPTED_KEY,
+)
 
 
 def test_extract_requested_slot_default():
@@ -1493,3 +1499,123 @@ async def test_submit(form_class: Type[FormAction]):
 def test_form_deprecation():
     with pytest.warns(FutureWarning):
         FormAction()
+
+
+class TestFormValidationAction(FormValidationAction):
+    def name(self) -> Text:
+        return "some_form"
+
+    def validate_slot1(
+        self,
+        slot_value: Any,
+        dispatcher: "CollectingDispatcher",
+        tracker: "Tracker",
+        domain: "DomainDict",
+    ) -> Dict[Text, Any]:
+        if slot_value == "correct_value":
+            return {
+                "slot1": "validated_value",
+            }
+        return {
+            "slot1": None,
+        }
+
+    def validate_slot2(
+        self,
+        slot_value: Any,
+        dispatcher: "CollectingDispatcher",
+        tracker: "Tracker",
+        domain: "DomainDict",
+    ) -> Dict[Text, Any]:
+        if slot_value == "correct_value":
+            return {
+                "slot2": "validated_value",
+            }
+        return {
+            "slot2": None,
+        }
+
+    async def validate_slot3(
+        self,
+        slot_value: Any,
+        dispatcher: "CollectingDispatcher",
+        tracker: "Tracker",
+        domain: "DomainDict",
+    ) -> Dict[Text, Any]:
+        if slot_value == "correct_value":
+            return {
+                "slot3": "validated_value",
+            }
+        # this function doesn't return anything when the slot value is incorrect
+
+
+async def test_form_validation_action():
+    form = TestFormValidationAction()
+
+    # tracker with active form
+    tracker = Tracker(
+        "default",
+        {},
+        {},
+        [SlotSet("slot1", "correct_value"), SlotSet("slot2", "incorrect_value")],
+        False,
+        None,
+        {"name": "some_form", "is_interrupted": False, "rejected": False},
+        "action_listen",
+    )
+
+    dispatcher = CollectingDispatcher()
+    events = await form.run(dispatcher=dispatcher, tracker=tracker, domain=None)
+    assert events == [
+        SlotSet("slot2", None),
+        SlotSet("slot1", "validated_value"),
+    ]
+
+
+async def test_form_validation_action_async():
+    form = TestFormValidationAction()
+
+    # tracker with active form
+    tracker = Tracker(
+        "default",
+        {},
+        {},
+        [SlotSet("slot3", "correct_value")],
+        False,
+        None,
+        {"name": "some_form", "is_interrupted": False, "rejected": False},
+        "action_listen",
+    )
+
+    dispatcher = CollectingDispatcher()
+    events = await form.run(dispatcher=dispatcher, tracker=tracker, domain=None)
+    assert events == [SlotSet("slot3", "validated_value")]
+
+
+async def test_form_validation_without_validate_function():
+    form = TestFormValidationAction()
+
+    # tracker with active form
+    tracker = Tracker(
+        "default",
+        {},
+        {},
+        [
+            SlotSet("slot1", "correct_value"),
+            SlotSet("slot2", "incorrect_value"),
+            SlotSet("slot3", "some_value"),
+        ],
+        False,
+        None,
+        {"name": "some_form", "is_interrupted": False, "rejected": False},
+        "action_listen",
+    )
+
+    dispatcher = CollectingDispatcher()
+    with pytest.warns(UserWarning):
+        events = await form.run(dispatcher=dispatcher, tracker=tracker, domain=None)
+        assert events == [
+            SlotSet("slot3", "some_value"),
+            SlotSet("slot2", None),
+            SlotSet("slot1", "validated_value"),
+        ]