diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3daeae109..6dfc4e915 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,2 +1,3 @@
 - Enhance firstore triggers (#1358).
 - Allow parametrized string type in ServiceAccount fields in Functions and trigger configs (#1309)
+- Adds support for region params (#1353).
diff --git a/src/v1/function-builder.ts b/src/v1/function-builder.ts
index 1812e3318..e70f26166 100644
--- a/src/v1/function-builder.ts
+++ b/src/v1/function-builder.ts
@@ -58,7 +58,10 @@ function assertRuntimeOptionsValid(runtimeOptions: RuntimeOptions): boolean {
       `The only valid memory allocation values are: ${VALID_MEMORY_OPTIONS.join(", ")}`
     );
   }
-  if (runtimeOptions.timeoutSeconds > MAX_TIMEOUT_SECONDS || runtimeOptions.timeoutSeconds < 0) {
+  if (
+    typeof runtimeOptions.timeoutSeconds === "number" &&
+    (runtimeOptions.timeoutSeconds > MAX_TIMEOUT_SECONDS || runtimeOptions.timeoutSeconds < 0)
+  ) {
     throw new Error(`TimeoutSeconds must be between 0 and ${MAX_TIMEOUT_SECONDS}`);
   }
 
@@ -236,7 +239,7 @@ function validateFailurePolicy(policy: any) {
  * @param regions list of regions.
  * @throws { Error } Regions must be in list of supported regions.
  */
-function assertRegionsAreValid(regions: string[]): boolean {
+function assertRegionsAreValid(regions: (string | Expression<string> | ResetValue)[]): boolean {
   if (!regions.length) {
     throw new Error("You must specify at least one region");
   }
@@ -252,7 +255,7 @@ function assertRegionsAreValid(regions: string[]): boolean {
  * functions.region('us-east1', 'us-central1')
  */
 export function region(
-  ...regions: Array<(typeof SUPPORTED_REGIONS)[number] | string>
+  ...regions: Array<(typeof SUPPORTED_REGIONS)[number] | string | Expression<string> | ResetValue>
 ): FunctionBuilder {
   if (assertRegionsAreValid(regions)) {
     return new FunctionBuilder({ regions });
@@ -294,7 +297,9 @@ export class FunctionBuilder {
    * @example
    * functions.region('us-east1', 'us-central1')
    */
-  region(...regions: Array<(typeof SUPPORTED_REGIONS)[number] | string>): FunctionBuilder {
+  region(
+    ...regions: Array<(typeof SUPPORTED_REGIONS)[number] | string | Expression<string> | ResetValue>
+  ): FunctionBuilder {
     if (assertRegionsAreValid(regions)) {
       this.options.regions = regions;
       return this;
diff --git a/src/v1/function-configuration.ts b/src/v1/function-configuration.ts
index 477646fe5..0527572ee 100644
--- a/src/v1/function-configuration.ts
+++ b/src/v1/function-configuration.ts
@@ -270,7 +270,7 @@ export interface DeploymentOptions extends RuntimeOptions {
   /**
    * Regions where function should be deployed.
    */
-  regions?: Array<(typeof SUPPORTED_REGIONS)[number] | string>;
+  regions?: Array<(typeof SUPPORTED_REGIONS)[number] | string | Expression<string> | ResetValue>;
   /**
    * Schedule for the scheduled function.
    */
diff --git a/src/v2/options.ts b/src/v2/options.ts
index f489588e1..6d31dfda1 100644
--- a/src/v2/options.ts
+++ b/src/v2/options.ts
@@ -102,7 +102,7 @@ export interface GlobalOptions {
   /**
    * Region where functions should be deployed.
    */
-  region?: SupportedRegion | string;
+  region?: SupportedRegion | string | Expression<string> | ResetValue;
 
   /**
    * Amount of memory to allocate to a function.
@@ -252,7 +252,7 @@ export interface EventHandlerOptions extends Omit<GlobalOptions, "enforceAppChec
 
   /** Region of the EventArc trigger. */
   // region?: string | Expression<string> | null;
-  region?: string;
+  region?: string | Expression<string> | ResetValue;
 
   /** The service account that EventArc should use to invoke this function. Requires the P4SA to have ActAs permission on this service account. */
   serviceAccount?: string | Expression<string> | ResetValue;
diff --git a/src/v2/providers/alerts/alerts.ts b/src/v2/providers/alerts/alerts.ts
index cfb3f64e3..050721f54 100644
--- a/src/v2/providers/alerts/alerts.ts
+++ b/src/v2/providers/alerts/alerts.ts
@@ -94,7 +94,7 @@ export interface FirebaseAlertOptions extends options.EventHandlerOptions {
   /**
    * Region where functions should be deployed.
    */
-  region?: options.SupportedRegion | string;
+  region?: options.SupportedRegion | string | Expression<string> | ResetValue;
 
   /**
    * Amount of memory to allocate to a function.
diff --git a/src/v2/providers/alerts/appDistribution.ts b/src/v2/providers/alerts/appDistribution.ts
index 7fb5833a1..239233d73 100644
--- a/src/v2/providers/alerts/appDistribution.ts
+++ b/src/v2/providers/alerts/appDistribution.ts
@@ -105,7 +105,7 @@ export interface AppDistributionOptions extends options.EventHandlerOptions {
   /**
    * Region where functions should be deployed.
    */
-  region?: options.SupportedRegion | string;
+  region?: options.SupportedRegion | string | Expression<string> | ResetValue;
 
   /**
    * Amount of memory to allocate to a function.
diff --git a/src/v2/providers/alerts/crashlytics.ts b/src/v2/providers/alerts/crashlytics.ts
index ea0566c13..0e9cb7d8d 100644
--- a/src/v2/providers/alerts/crashlytics.ts
+++ b/src/v2/providers/alerts/crashlytics.ts
@@ -185,7 +185,7 @@ export interface CrashlyticsOptions extends options.EventHandlerOptions {
   /**
    * Region where functions should be deployed.
    */
-  region?: options.SupportedRegion | string;
+  region?: options.SupportedRegion | string | Expression<string> | ResetValue;
 
   /**
    * Amount of memory to allocate to a function.
diff --git a/src/v2/providers/database.ts b/src/v2/providers/database.ts
index dbf7dbdb6..c3318855c 100644
--- a/src/v2/providers/database.ts
+++ b/src/v2/providers/database.ts
@@ -106,7 +106,7 @@ export interface ReferenceOptions<Ref extends string = string> extends options.E
   /**
    * Region where functions should be deployed.
    */
-  region?: options.SupportedRegion | string;
+  region?: options.SupportedRegion | string | Expression<string> | ResetValue;
 
   /**
    * Amount of memory to allocate to a function.
diff --git a/src/v2/providers/eventarc.ts b/src/v2/providers/eventarc.ts
index 3d1a696cb..6d980e2f9 100644
--- a/src/v2/providers/eventarc.ts
+++ b/src/v2/providers/eventarc.ts
@@ -70,7 +70,7 @@ export interface EventarcTriggerOptions extends options.EventHandlerOptions {
   /**
    * Region where functions should be deployed.
    */
-  region?: options.SupportedRegion | string;
+  region?: options.SupportedRegion | string | Expression<string> | ResetValue;
 
   /**
    * Amount of memory to allocate to a function.
diff --git a/src/v2/providers/https.ts b/src/v2/providers/https.ts
index 80def4273..461c632f2 100644
--- a/src/v2/providers/https.ts
+++ b/src/v2/providers/https.ts
@@ -56,7 +56,12 @@ export interface HttpsOptions extends Omit<GlobalOptions, "region"> {
   omit?: boolean | Expression<boolean>;
 
   /** HTTP functions can override global options and can specify multiple regions to deploy to. */
-  region?: SupportedRegion | string | Array<SupportedRegion | string>;
+  region?:
+    | SupportedRegion
+    | string
+    | Array<SupportedRegion | string>
+    | Expression<string>
+    | ResetValue;
 
   /** If true, allows CORS on requests to this function.
    * If this is a `string` or `RegExp`, allows requests from domains that match the provided value.
diff --git a/src/v2/providers/identity.ts b/src/v2/providers/identity.ts
index 7e8e5d5aa..3a0b1b7fc 100644
--- a/src/v2/providers/identity.ts
+++ b/src/v2/providers/identity.ts
@@ -72,7 +72,7 @@ export interface BlockingOptions {
   /**
    * Region where functions should be deployed.
    */
-  region?: options.SupportedRegion | string;
+  region?: options.SupportedRegion | string | Expression<string> | ResetValue;
 
   /**
    * Amount of memory to allocate to a function.
diff --git a/src/v2/providers/pubsub.ts b/src/v2/providers/pubsub.ts
index e95eca7b6..19e368d41 100644
--- a/src/v2/providers/pubsub.ts
+++ b/src/v2/providers/pubsub.ts
@@ -163,7 +163,7 @@ export interface PubSubOptions extends options.EventHandlerOptions {
   /**
    * Region where functions should be deployed.
    */
-  region?: options.SupportedRegion | string;
+  region?: options.SupportedRegion | string | Expression<string> | ResetValue;
 
   /**
    * Amount of memory to allocate to a function.
diff --git a/src/v2/providers/storage.ts b/src/v2/providers/storage.ts
index 248eb1869..451a257b5 100644
--- a/src/v2/providers/storage.ts
+++ b/src/v2/providers/storage.ts
@@ -211,7 +211,7 @@ export interface StorageOptions extends options.EventHandlerOptions {
   /**
    * Region where functions should be deployed.
    */
-  region?: options.SupportedRegion | string;
+  region?: options.SupportedRegion | string | Expression<string> | ResetValue;
 
   /**
    * Amount of memory to allocate to a function.
diff --git a/src/v2/providers/tasks.ts b/src/v2/providers/tasks.ts
index 442c92178..304dd907f 100644
--- a/src/v2/providers/tasks.ts
+++ b/src/v2/providers/tasks.ts
@@ -68,7 +68,7 @@ export interface TaskQueueOptions extends options.EventHandlerOptions {
   /**
    * Region where functions should be deployed.
    */
-  region?: options.SupportedRegion | string;
+  region?: options.SupportedRegion | string | Expression<string> | ResetValue;
 
   /**
    * Amount of memory to allocate to a function.