diff --git a/github/enterprise_properties_test.go b/github/enterprise_properties_test.go
index 3155f9669bc..c78c17e6d75 100644
--- a/github/enterprise_properties_test.go
+++ b/github/enterprise_properties_test.go
@@ -56,7 +56,7 @@ func TestEnterpriseService_GetAllCustomProperties(t *testing.T) {
 			PropertyName:     Ptr("name"),
 			ValueType:        "single_select",
 			Required:         Ptr(true),
-			DefaultValue:     Ptr("production"),
+			DefaultValue:     "production",
 			Description:      Ptr("Prod or dev environment"),
 			AllowedValues:    []string{"production", "development"},
 			ValuesEditableBy: Ptr("org_actors"),
@@ -92,7 +92,7 @@ func TestEnterpriseService_CreateOrUpdateCustomProperties(t *testing.T) {
 
 	mux.HandleFunc("/enterprises/e/properties/schema", func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "PATCH")
-		testBody(t, r, `{"properties":[{"property_name":"name","value_type":"single_select","required":true},{"property_name":"service","value_type":"string"}]}`+"\n")
+		testBody(t, r, `{"properties":[{"property_name":"name","value_type":"single_select","required":true,"default_value":null},{"property_name":"service","value_type":"string","default_value":null}]}`+"\n")
 		fmt.Fprint(w, `[
 		{
           "property_name": "name",
@@ -179,7 +179,7 @@ func TestEnterpriseService_GetCustomProperty(t *testing.T) {
 		PropertyName:     Ptr("name"),
 		ValueType:        "single_select",
 		Required:         Ptr(true),
-		DefaultValue:     Ptr("production"),
+		DefaultValue:     "production",
 		Description:      Ptr("Prod or dev environment"),
 		AllowedValues:    []string{"production", "development"},
 		ValuesEditableBy: Ptr("org_actors"),
@@ -223,7 +223,7 @@ func TestEnterpriseService_CreateOrUpdateCustomProperty(t *testing.T) {
 	property, _, err := client.Enterprise.CreateOrUpdateCustomProperty(ctx, "e", "name", &CustomProperty{
 		ValueType:        "single_select",
 		Required:         Ptr(true),
-		DefaultValue:     Ptr("production"),
+		DefaultValue:     "production",
 		Description:      Ptr("Prod or dev environment"),
 		AllowedValues:    []string{"production", "development"},
 		ValuesEditableBy: Ptr("org_actors"),
@@ -236,7 +236,7 @@ func TestEnterpriseService_CreateOrUpdateCustomProperty(t *testing.T) {
 		PropertyName:     Ptr("name"),
 		ValueType:        "single_select",
 		Required:         Ptr(true),
-		DefaultValue:     Ptr("production"),
+		DefaultValue:     "production",
 		Description:      Ptr("Prod or dev environment"),
 		AllowedValues:    []string{"production", "development"},
 		ValuesEditableBy: Ptr("org_actors"),
diff --git a/github/event_types_test.go b/github/event_types_test.go
index 9ad223dca69..2c0cca2e07c 100644
--- a/github/event_types_test.go
+++ b/github/event_types_test.go
@@ -13735,7 +13735,7 @@ func TestCustomPropertyEvent_Marshal(t *testing.T) {
 			ValueType:        "single_select",
 			SourceType:       Ptr("enterprise"),
 			Required:         Ptr(true),
-			DefaultValue:     Ptr("production"),
+			DefaultValue:     "production",
 			Description:      Ptr("Prod or dev environment"),
 			AllowedValues:    []string{"production", "development"},
 			ValuesEditableBy: Ptr("org_actors"),
diff --git a/github/github-accessors.go b/github/github-accessors.go
index 0a8f83ee2e1..d3c0d0d1df7 100644
--- a/github/github-accessors.go
+++ b/github/github-accessors.go
@@ -6734,14 +6734,6 @@ func (c *CustomOrgRoles) GetUpdatedAt() Timestamp {
 	return *c.UpdatedAt
 }
 
-// GetDefaultValue returns the DefaultValue field if it's non-nil, zero value otherwise.
-func (c *CustomProperty) GetDefaultValue() string {
-	if c == nil || c.DefaultValue == nil {
-		return ""
-	}
-	return *c.DefaultValue
-}
-
 // GetDescription returns the Description field if it's non-nil, zero value otherwise.
 func (c *CustomProperty) GetDescription() string {
 	if c == nil || c.Description == nil {
diff --git a/github/github-accessors_test.go b/github/github-accessors_test.go
index 3c78a1436b8..18237768776 100644
--- a/github/github-accessors_test.go
+++ b/github/github-accessors_test.go
@@ -8802,17 +8802,6 @@ func TestCustomOrgRoles_GetUpdatedAt(tt *testing.T) {
 	c.GetUpdatedAt()
 }
 
-func TestCustomProperty_GetDefaultValue(tt *testing.T) {
-	tt.Parallel()
-	var zeroValue string
-	c := &CustomProperty{DefaultValue: &zeroValue}
-	c.GetDefaultValue()
-	c = &CustomProperty{}
-	c.GetDefaultValue()
-	c = nil
-	c.GetDefaultValue()
-}
-
 func TestCustomProperty_GetDescription(tt *testing.T) {
 	tt.Parallel()
 	var zeroValue string
diff --git a/github/orgs_properties.go b/github/orgs_properties.go
index 257e765993b..7cf89db2de3 100644
--- a/github/orgs_properties.go
+++ b/github/orgs_properties.go
@@ -23,8 +23,8 @@ type CustomProperty struct {
 	ValueType string `json:"value_type"`
 	// Whether the property is required.
 	Required *bool `json:"required,omitempty"`
-	// Default value of the property.
-	DefaultValue *string `json:"default_value,omitempty"`
+	// Default value of the property. Can be null, string or array of strings.
+	DefaultValue any `json:"default_value"`
 	// Short description of the property.
 	Description *string `json:"description,omitempty"`
 	// An ordered list of the allowed values of the property. The property can have up to 200
diff --git a/github/orgs_properties_test.go b/github/orgs_properties_test.go
index e8bf5fe6502..e99f0ee2e50 100644
--- a/github/orgs_properties_test.go
+++ b/github/orgs_properties_test.go
@@ -41,6 +41,11 @@ func TestOrganizationsService_GetAllCustomProperties(t *testing.T) {
           "property_name": "team",
           "value_type": "string",
           "description": "Team owning the repository"
+        },
+		{
+          "property_name": "multi_select_property",
+		  "value_type": "multi_select",
+          "default_value": ["production", "development"]
         }
         ]`)
 	})
@@ -56,7 +61,7 @@ func TestOrganizationsService_GetAllCustomProperties(t *testing.T) {
 			PropertyName:     Ptr("name"),
 			ValueType:        "single_select",
 			Required:         Ptr(true),
-			DefaultValue:     Ptr("production"),
+			DefaultValue:     "production",
 			Description:      Ptr("Prod or dev environment"),
 			AllowedValues:    []string{"production", "development"},
 			ValuesEditableBy: Ptr("org_actors"),
@@ -70,6 +75,11 @@ func TestOrganizationsService_GetAllCustomProperties(t *testing.T) {
 			ValueType:    "string",
 			Description:  Ptr("Team owning the repository"),
 		},
+		{
+			PropertyName: Ptr("multi_select_property"),
+			ValueType:    "multi_select",
+			DefaultValue: []any{"production", "development"},
+		},
 	}
 	if !cmp.Equal(properties, want) {
 		t.Errorf("Organizations.GetAllCustomProperties returned %+v, want %+v", properties, want)
@@ -92,7 +102,11 @@ func TestOrganizationsService_CreateOrUpdateCustomProperties(t *testing.T) {
 
 	mux.HandleFunc("/orgs/o/properties/schema", func(w http.ResponseWriter, r *http.Request) {
 		testMethod(t, r, "PATCH")
-		testBody(t, r, `{"properties":[{"property_name":"name","value_type":"single_select","required":true},{"property_name":"service","value_type":"string"}]}`+"\n")
+		testBody(t, r, fmt.Sprintf(`{"properties":[%s,%s,%s,%s]}`+"\n",
+			`{"property_name":"name","value_type":"single_select","required":true,"default_value":null}`,
+			`{"property_name":"service","value_type":"string","default_value":null}`,
+			`{"property_name":"multi_select_property","value_type":"multi_select","default_value":["production","development"]}`,
+			`{"property_name":"multi_select_property_null","value_type":"multi_select","default_value":null}`))
 		fmt.Fprint(w, `[
 		{
           "property_name": "name",
@@ -102,6 +116,16 @@ func TestOrganizationsService_CreateOrUpdateCustomProperties(t *testing.T) {
         {
           "property_name": "service",
           "value_type": "string"
+        },
+        {
+          "property_name": "multi_select_property",
+          "value_type": "multi_select",
+          "default_value": ["production", "development"]
+        },
+        {
+          "property_name": "multi_select_property_null",
+          "value_type": "multi_select",
+          "default_value": null
         }
         ]`)
 	})
@@ -117,6 +141,16 @@ func TestOrganizationsService_CreateOrUpdateCustomProperties(t *testing.T) {
 			PropertyName: Ptr("service"),
 			ValueType:    "string",
 		},
+		{
+			PropertyName: Ptr("multi_select_property"),
+			ValueType:    "multi_select",
+			DefaultValue: []any{"production", "development"},
+		},
+		{
+			PropertyName: Ptr("multi_select_property_null"),
+			ValueType:    "multi_select",
+			DefaultValue: nil,
+		},
 	})
 	if err != nil {
 		t.Errorf("Organizations.CreateOrUpdateCustomProperties returned error: %v", err)
@@ -132,6 +166,16 @@ func TestOrganizationsService_CreateOrUpdateCustomProperties(t *testing.T) {
 			PropertyName: Ptr("service"),
 			ValueType:    "string",
 		},
+		{
+			PropertyName: Ptr("multi_select_property"),
+			ValueType:    "multi_select",
+			DefaultValue: []any{"production", "development"},
+		},
+		{
+			PropertyName: Ptr("multi_select_property_null"),
+			ValueType:    "multi_select",
+			DefaultValue: nil,
+		},
 	}
 
 	if !cmp.Equal(properties, want) {
@@ -179,7 +223,7 @@ func TestOrganizationsService_GetCustomProperty(t *testing.T) {
 		PropertyName:     Ptr("name"),
 		ValueType:        "single_select",
 		Required:         Ptr(true),
-		DefaultValue:     Ptr("production"),
+		DefaultValue:     "production",
 		Description:      Ptr("Prod or dev environment"),
 		AllowedValues:    []string{"production", "development"},
 		ValuesEditableBy: Ptr("org_actors"),
@@ -223,7 +267,7 @@ func TestOrganizationsService_CreateOrUpdateCustomProperty(t *testing.T) {
 	property, _, err := client.Organizations.CreateOrUpdateCustomProperty(ctx, "o", "name", &CustomProperty{
 		ValueType:        "single_select",
 		Required:         Ptr(true),
-		DefaultValue:     Ptr("production"),
+		DefaultValue:     "production",
 		Description:      Ptr("Prod or dev environment"),
 		AllowedValues:    []string{"production", "development"},
 		ValuesEditableBy: Ptr("org_actors"),
@@ -236,7 +280,7 @@ func TestOrganizationsService_CreateOrUpdateCustomProperty(t *testing.T) {
 		PropertyName:     Ptr("name"),
 		ValueType:        "single_select",
 		Required:         Ptr(true),
-		DefaultValue:     Ptr("production"),
+		DefaultValue:     "production",
 		Description:      Ptr("Prod or dev environment"),
 		AllowedValues:    []string{"production", "development"},
 		ValuesEditableBy: Ptr("org_actors"),