diff --git a/.changelog/3218.txt b/.changelog/3218.txt
new file mode 100644
index 00000000000..511ee632569
--- /dev/null
+++ b/.changelog/3218.txt
@@ -0,0 +1,3 @@
+```release-note:breaking-change
+dialogflow: Changed `google_dialogflow_agent.time_zone` to ForceNew. Updating this field will require recreation. This is due to a change in API behavior.
+```
diff --git a/google/resource_dialogflow_agent.go b/google/resource_dialogflow_agent.go
index 8cdacd2893b..4f0e11972e0 100644
--- a/google/resource_dialogflow_agent.go
+++ b/google/resource_dialogflow_agent.go
@@ -58,6 +58,7 @@ for a list of the currently supported language codes. This field cannot be updat
 			"time_zone": {
 				Type:     schema.TypeString,
 				Required: true,
+				ForceNew: true,
 				Description: `The time zone of this agent from the [time zone database](https://www.iana.org/time-zones), e.g., America/New_York,
 Europe/Paris.`,
 			},
diff --git a/google/resource_dialogflow_agent_test.go b/google/resource_dialogflow_agent_test.go
index 46775491b0f..2b5e8911371 100644
--- a/google/resource_dialogflow_agent_test.go
+++ b/google/resource_dialogflow_agent_test.go
@@ -105,7 +105,7 @@ func testAccDialogflowAgent_full2(projectID string, orgID string, agentName stri
 		display_name = "%s"
 		default_language_code = "en"
 		supported_language_codes = ["no"]
-		time_zone = "Europe/London"
+		time_zone = "America/New_York"
 		description = "Description 2!"
 		avatar_uri = "https://storage.googleapis.com/gweb-cloudblog-publish/images/f4xvje.max-200x200.PNG"
 		enable_logging = false