diff --git a/src/validations/index.ts b/src/validations/index.ts
index ba48e05da..440609eae 100644
--- a/src/validations/index.ts
+++ b/src/validations/index.ts
@@ -1,9 +1,11 @@
 import basic from './basic';
 import aaveSpaceValidation from './aave';
 import nounsSpaceValidation from './nouns';
+import timeperiodSpaceValidation from './timeperiod';
 
 export default {
   basic,
   aave: aaveSpaceValidation,
-  nouns: nounsSpaceValidation
+  nouns: nounsSpaceValidation,
+  timeperiod: timeperiodSpaceValidation
 };
diff --git a/src/validations/timeperiod/examples.json b/src/validations/timeperiod/examples.json
new file mode 100644
index 000000000..02381e38e
--- /dev/null
+++ b/src/validations/timeperiod/examples.json
@@ -0,0 +1,14 @@
+[
+  {
+    "name": "Example of a prop entry time constrained validation",
+    "validation": {
+      "name": "timeperiod",
+      "params": {
+        "propEntryStart": 1659108444521,
+        "propEntryEnd": 1659194844521
+      }
+    },
+    "network": "1",
+    "userAddress": ""
+  }
+]
diff --git a/src/validations/timeperiod/index.ts b/src/validations/timeperiod/index.ts
new file mode 100644
index 000000000..193ab54c7
--- /dev/null
+++ b/src/validations/timeperiod/index.ts
@@ -0,0 +1,27 @@
+export default async function validate(
+  author: string,
+  space,
+  proposal,
+  options
+): Promise<boolean> {
+  const onlyMembers = options.onlyMembers || space.filters?.onlyMembers;
+  const members = (space.members || []).map((address) => address.toLowerCase());
+  const {propEntryStart = 0, propEntryEnd = 0} = options; 
+
+  if (!propEntryStart || !propEntryEnd || (propEntryStart >= propEntryEnd)) return false;
+
+  if (members.includes(author.toLowerCase())) return true;
+
+  if (onlyMembers) return false;
+
+  const now       = new Date().getTime();
+  const startTime = new Date(propEntryStart).getTime();
+  const endTime   = new Date(propEntryEnd).getTime();
+
+  // Only allow proposals being submitted in this time window.
+  if (now >= startTime &&  now <= endTime) {
+    return true;
+  } 
+
+  return false;
+}