diff --git a/.changelog/11304.txt b/.changelog/11304.txt
new file mode 100644
index 00000000000..60f9fff9817
--- /dev/null
+++ b/.changelog/11304.txt
@@ -0,0 +1,3 @@
+```release-note:breaking-change
+bigqueryreservation: remove `multi_region_auxiliary` from `google_bigquery_reservation`
+```
\ No newline at end of file
diff --git a/google/services/bigqueryreservation/resource_bigquery_reservation.go b/google/services/bigqueryreservation/resource_bigquery_reservation.go
index c0392df667f..d46f8adb0ed 100644
--- a/google/services/bigqueryreservation/resource_bigquery_reservation.go
+++ b/google/services/bigqueryreservation/resource_bigquery_reservation.go
@@ -115,13 +115,6 @@ capacity specified above at most.`,
 Examples: US, EU, asia-northeast1. The default value is US.`,
 				Default: "US",
 			},
-			"multi_region_auxiliary": {
-				Type:       schema.TypeBool,
-				Optional:   true,
-				Deprecated: "`multi_region_auxiliary` is deprecated and will be removed in a future major release. This field is no longer supported by the BigQuery Reservation API.",
-				Description: `Applicable only for reservations located within one of the BigQuery multi-regions (US or EU).
-If set to true, this reservation is placed in the organization's secondary region which is designated for disaster recovery purposes. If false, this reservation is placed in the organization's default region.`,
-			},
 			"project": {
 				Type:     schema.TypeString,
 				Optional: true,
@@ -159,12 +152,6 @@ func resourceBigqueryReservationReservationCreate(d *schema.ResourceData, meta i
 	} else if v, ok := d.GetOkExists("concurrency"); !tpgresource.IsEmptyValue(reflect.ValueOf(concurrencyProp)) && (ok || !reflect.DeepEqual(v, concurrencyProp)) {
 		obj["concurrency"] = concurrencyProp
 	}
-	multiRegionAuxiliaryProp, err := expandBigqueryReservationReservationMultiRegionAuxiliary(d.Get("multi_region_auxiliary"), d, config)
-	if err != nil {
-		return err
-	} else if v, ok := d.GetOkExists("multi_region_auxiliary"); !tpgresource.IsEmptyValue(reflect.ValueOf(multiRegionAuxiliaryProp)) && (ok || !reflect.DeepEqual(v, multiRegionAuxiliaryProp)) {
-		obj["multiRegionAuxiliary"] = multiRegionAuxiliaryProp
-	}
 	editionProp, err := expandBigqueryReservationReservationEdition(d.Get("edition"), d, config)
 	if err != nil {
 		return err
@@ -275,9 +262,6 @@ func resourceBigqueryReservationReservationRead(d *schema.ResourceData, meta int
 	if err := d.Set("concurrency", flattenBigqueryReservationReservationConcurrency(res["concurrency"], d, config)); err != nil {
 		return fmt.Errorf("Error reading Reservation: %s", err)
 	}
-	if err := d.Set("multi_region_auxiliary", flattenBigqueryReservationReservationMultiRegionAuxiliary(res["multiRegionAuxiliary"], d, config)); err != nil {
-		return fmt.Errorf("Error reading Reservation: %s", err)
-	}
 	if err := d.Set("edition", flattenBigqueryReservationReservationEdition(res["edition"], d, config)); err != nil {
 		return fmt.Errorf("Error reading Reservation: %s", err)
 	}
@@ -322,12 +306,6 @@ func resourceBigqueryReservationReservationUpdate(d *schema.ResourceData, meta i
 	} else if v, ok := d.GetOkExists("concurrency"); !tpgresource.IsEmptyValue(reflect.ValueOf(v)) && (ok || !reflect.DeepEqual(v, concurrencyProp)) {
 		obj["concurrency"] = concurrencyProp
 	}
-	multiRegionAuxiliaryProp, err := expandBigqueryReservationReservationMultiRegionAuxiliary(d.Get("multi_region_auxiliary"), d, config)
-	if err != nil {
-		return err
-	} else if v, ok := d.GetOkExists("multi_region_auxiliary"); !tpgresource.IsEmptyValue(reflect.ValueOf(v)) && (ok || !reflect.DeepEqual(v, multiRegionAuxiliaryProp)) {
-		obj["multiRegionAuxiliary"] = multiRegionAuxiliaryProp
-	}
 	autoscaleProp, err := expandBigqueryReservationReservationAutoscale(d.Get("autoscale"), d, config)
 	if err != nil {
 		return err
@@ -356,10 +334,6 @@ func resourceBigqueryReservationReservationUpdate(d *schema.ResourceData, meta i
 		updateMask = append(updateMask, "concurrency")
 	}
 
-	if d.HasChange("multi_region_auxiliary") {
-		updateMask = append(updateMask, "multiRegionAuxiliary")
-	}
-
 	if d.HasChange("autoscale") {
 		updateMask = append(updateMask, "autoscale")
 	}
@@ -505,10 +479,6 @@ func flattenBigqueryReservationReservationConcurrency(v interface{}, d *schema.R
 	return v // let terraform core handle it otherwise
 }
 
-func flattenBigqueryReservationReservationMultiRegionAuxiliary(v interface{}, d *schema.ResourceData, config *transport_tpg.Config) interface{} {
-	return v
-}
-
 func flattenBigqueryReservationReservationEdition(v interface{}, d *schema.ResourceData, config *transport_tpg.Config) interface{} {
 	return v
 }
@@ -574,10 +544,6 @@ func expandBigqueryReservationReservationConcurrency(v interface{}, d tpgresourc
 	return v, nil
 }
 
-func expandBigqueryReservationReservationMultiRegionAuxiliary(v interface{}, d tpgresource.TerraformResourceData, config *transport_tpg.Config) (interface{}, error) {
-	return v, nil
-}
-
 func expandBigqueryReservationReservationEdition(v interface{}, d tpgresource.TerraformResourceData, config *transport_tpg.Config) (interface{}, error) {
 	return v, nil
 }
diff --git a/website/docs/guides/version_6_upgrade.html.markdown b/website/docs/guides/version_6_upgrade.html.markdown
index d961765c3c9..ed159e6a7bd 100644
--- a/website/docs/guides/version_6_upgrade.html.markdown
+++ b/website/docs/guides/version_6_upgrade.html.markdown
@@ -108,6 +108,12 @@ Description of the change and how users should adjust their configuration (if ne
 
 A `view` can no longer be created when `schema` contains required fields
 
+## Resource: `google_bigquery_reservation`
+
+### `multi_region_auxiliary` is now removed
+
+This field is no longer supported by the BigQuery Reservation API.
+
 ## Resource: `google_sql_database_instance`
 
 ### `settings.ip_configuration.require_ssl` is now removed
diff --git a/website/docs/r/bigquery_reservation.html.markdown b/website/docs/r/bigquery_reservation.html.markdown
index 89af961cbf0..7fd23494599 100644
--- a/website/docs/r/bigquery_reservation.html.markdown
+++ b/website/docs/r/bigquery_reservation.html.markdown
@@ -80,13 +80,6 @@ The following arguments are supported:
   (Optional)
   Maximum number of queries that are allowed to run concurrently in this reservation. This is a soft limit due to asynchronous nature of the system and various optimizations for small queries. Default value is 0 which means that concurrency will be automatically set based on the reservation size.
 
-* `multi_region_auxiliary` -
-  (Optional, Deprecated)
-  Applicable only for reservations located within one of the BigQuery multi-regions (US or EU).
-  If set to true, this reservation is placed in the organization's secondary region which is designated for disaster recovery purposes. If false, this reservation is placed in the organization's default region.
-
-  ~> **Warning:** `multi_region_auxiliary` is deprecated and will be removed in a future major release. This field is no longer supported by the BigQuery Reservation API.
-
 * `edition` -
   (Optional)
   The edition type. Valid values are STANDARD, ENTERPRISE, ENTERPRISE_PLUS