diff --git a/docs/resources/keycloak_openid_user_attribute_protocol_mapper.md b/docs/resources/keycloak_openid_user_attribute_protocol_mapper.md
index a7ea7a888..244a340a8 100644
--- a/docs/resources/keycloak_openid_user_attribute_protocol_mapper.md
+++ b/docs/resources/keycloak_openid_user_attribute_protocol_mapper.md
@@ -77,7 +77,7 @@ The following arguments are supported:
 - `add_to_id_token` - (Optional) Indicates if the attribute should be added as a claim to the id token. Defaults to `true`.
 - `add_to_access_token` - (Optional) Indicates if the attribute should be added as a claim to the access token. Defaults to `true`.
 - `add_to_userinfo` - (Optional) Indicates if the attribute should be added as a claim to the UserInfo response body. Defaults to `true`.
-
+- `aggregate_attributes`- (Optional) Indicates whether this attribute is a single value or an array of values. Defaults to `false`.
 ### Import
 
 Protocol mappers can be imported using one of the following formats:
diff --git a/keycloak/openid_user_attribute_protocol_mapper.go b/keycloak/openid_user_attribute_protocol_mapper.go
index ea9faf3a8..5a92d5628 100644
--- a/keycloak/openid_user_attribute_protocol_mapper.go
+++ b/keycloak/openid_user_attribute_protocol_mapper.go
@@ -20,7 +20,8 @@ type OpenIdUserAttributeProtocolMapper struct {
 	ClaimName      string
 	ClaimValueType string
 
-	Multivalued bool // indicates whether is this an array of attributes or a single attribute
+	Multivalued              bool // indicates whether is this an array of attributes or a single attribute
+	AggregateAttributeValues bool
 }
 
 func (mapper *OpenIdUserAttributeProtocolMapper) convertToGenericProtocolMapper() *protocolMapper {
@@ -30,13 +31,14 @@ func (mapper *OpenIdUserAttributeProtocolMapper) convertToGenericProtocolMapper(
 		Protocol:       "openid-connect",
 		ProtocolMapper: "oidc-usermodel-attribute-mapper",
 		Config: map[string]string{
-			addToIdTokenField:     strconv.FormatBool(mapper.AddToIdToken),
-			addToAccessTokenField: strconv.FormatBool(mapper.AddToAccessToken),
-			addToUserInfoField:    strconv.FormatBool(mapper.AddToUserInfo),
-			userAttributeField:    mapper.UserAttribute,
-			claimNameField:        mapper.ClaimName,
-			claimValueTypeField:   mapper.ClaimValueType,
-			multivaluedField:      strconv.FormatBool(mapper.Multivalued),
+			addToIdTokenField:             strconv.FormatBool(mapper.AddToIdToken),
+			addToAccessTokenField:         strconv.FormatBool(mapper.AddToAccessToken),
+			addToUserInfoField:            strconv.FormatBool(mapper.AddToUserInfo),
+			userAttributeField:            mapper.UserAttribute,
+			claimNameField:                mapper.ClaimName,
+			claimValueTypeField:           mapper.ClaimValueType,
+			multivaluedField:              strconv.FormatBool(mapper.Multivalued),
+			aggregateAttributeValuesField: strconv.FormatBool(mapper.AggregateAttributeValues),
 		},
 	}
 }
@@ -63,6 +65,11 @@ func (protocolMapper *protocolMapper) convertToOpenIdUserAttributeProtocolMapper
 		return nil, err
 	}
 
+	aggregateAttributeValues, err := strconv.ParseBool(protocolMapper.Config[aggregateAttributeValuesField])
+	if err != nil {
+		return nil, err
+	}
+
 	return &OpenIdUserAttributeProtocolMapper{
 		Id:            protocolMapper.Id,
 		Name:          protocolMapper.Name,
@@ -74,10 +81,11 @@ func (protocolMapper *protocolMapper) convertToOpenIdUserAttributeProtocolMapper
 		AddToAccessToken: addToAccessToken,
 		AddToUserInfo:    addToUserInfo,
 
-		UserAttribute:  protocolMapper.Config[userAttributeField],
-		ClaimName:      protocolMapper.Config[claimNameField],
-		ClaimValueType: protocolMapper.Config[claimValueTypeField],
-		Multivalued:    multivalued,
+		UserAttribute:            protocolMapper.Config[userAttributeField],
+		ClaimName:                protocolMapper.Config[claimNameField],
+		ClaimValueType:           protocolMapper.Config[claimValueTypeField],
+		Multivalued:              multivalued,
+		AggregateAttributeValues: aggregateAttributeValues,
 	}, nil
 }
 
diff --git a/keycloak/protocol_mapper.go b/keycloak/protocol_mapper.go
index a72d57e4b..b041e36e8 100644
--- a/keycloak/protocol_mapper.go
+++ b/keycloak/protocol_mapper.go
@@ -28,6 +28,7 @@ var (
 	userAttributeField                  = "user.attribute"
 	userPropertyField                   = "user.attribute"
 	userRealmRoleMappingRolePrefixField = "usermodel.realmRoleMapping.rolePrefix"
+	aggregateAttributeValuesField       = "aggregate.attrs"
 )
 
 func protocolMapperPath(realmId, clientId, clientScopeId string) string {
diff --git a/provider/resource_keycloak_openid_user_attribute_protocol_mapper.go b/provider/resource_keycloak_openid_user_attribute_protocol_mapper.go
index 0800d0d04..1e87ca8a3 100644
--- a/provider/resource_keycloak_openid_user_attribute_protocol_mapper.go
+++ b/provider/resource_keycloak_openid_user_attribute_protocol_mapper.go
@@ -84,6 +84,12 @@ func resourceKeycloakOpenIdUserAttributeProtocolMapper() *schema.Resource {
 				Default:      "String",
 				ValidateFunc: validation.StringInSlice([]string{"JSON", "String", "long", "int", "boolean"}, true),
 			},
+			"aggregate_attributes": {
+				Type:        schema.TypeBool,
+				Optional:    true,
+				Default:     false,
+				Description: "Indicates if attribute values should be aggregated within the group attributes",
+			},
 		},
 	}
 }
@@ -99,10 +105,11 @@ func mapFromDataToOpenIdUserAttributeProtocolMapper(data *schema.ResourceData) *
 		AddToAccessToken: data.Get("add_to_access_token").(bool),
 		AddToUserInfo:    data.Get("add_to_userinfo").(bool),
 
-		UserAttribute:  data.Get("user_attribute").(string),
-		ClaimName:      data.Get("claim_name").(string),
-		ClaimValueType: data.Get("claim_value_type").(string),
-		Multivalued:    data.Get("multivalued").(bool),
+		UserAttribute:            data.Get("user_attribute").(string),
+		ClaimName:                data.Get("claim_name").(string),
+		ClaimValueType:           data.Get("claim_value_type").(string),
+		Multivalued:              data.Get("multivalued").(bool),
+		AggregateAttributeValues: data.Get("aggregate_attributes").(bool),
 	}
 }
 
@@ -124,6 +131,7 @@ func mapFromOpenIdUserAttributeMapperToData(mapper *keycloak.OpenIdUserAttribute
 	data.Set("claim_name", mapper.ClaimName)
 	data.Set("claim_value_type", mapper.ClaimValueType)
 	data.Set("multivalued", mapper.Multivalued)
+	data.Set("aggregate_attributes", mapper.AggregateAttributeValues)
 }
 
 func resourceKeycloakOpenIdUserAttributeProtocolMapperCreate(data *schema.ResourceData, meta interface{}) error {