diff --git a/src/as-agreement.c b/src/as-agreement.c
index 70fa5e67..9148cb96 100644
--- a/src/as-agreement.c
+++ b/src/as-agreement.c
@@ -213,7 +213,7 @@ as_agreement_get_sections (AsAgreement *agreement)
  *
  * Gets the first section in the agreement.
  *
- * Returns: (transfer none): agreement section, or %NULL
+ * Returns: (transfer none) (nullable): agreement section, or %NULL
  *
  * Since: 0.12.1
  **/
diff --git a/src/as-metadata.c b/src/as-metadata.c
index 0847b191..9d5096a6 100644
--- a/src/as-metadata.c
+++ b/src/as-metadata.c
@@ -311,7 +311,7 @@ as_metadata_xml_parse_components_node (AsMetadata *metad, AsContext *context, xm
  *
  * Read an array of #AsComponent from AppStream YAML metadata.
  *
- * Returns: (transfer container) (element-type AsComponent): An array of #AsComponent or %NULL
+ * Returns: (transfer container) (element-type AsComponent) (nullable): An array of #AsComponent or %NULL
  */
 static GPtrArray*
 as_metadata_yaml_parse_collection_doc (AsMetadata *metad, AsContext *context, const gchar *data, GError **error)
@@ -1098,7 +1098,7 @@ as_metadata_add_component (AsMetadata *metad, AsComponent *cpt)
  * If the AppStream XML contained multiple components, return the first
  * component that has been parsed.
  *
- * Returns: (transfer none): An #AsComponent or %NULL
+ * Returns: (transfer none) (nullable): An #AsComponent or %NULL
  **/
 AsComponent*
 as_metadata_get_component (AsMetadata *metad)
diff --git a/src/as-release.c b/src/as-release.c
index e0908264..1e238da0 100644
--- a/src/as-release.c
+++ b/src/as-release.c
@@ -232,7 +232,7 @@ as_release_set_kind (AsRelease *release, AsReleaseKind kind)
  *
  * Gets the release version.
  *
- * Returns: string, or %NULL for not set or invalid
+ * Returns: (nullable): string, or %NULL for not set or invalid
  **/
 const gchar*
 as_release_get_version (AsRelease *release)
@@ -380,7 +380,7 @@ as_release_set_size (AsRelease *release, guint64 size, AsSizeKind kind)
  *
  * Gets the release description markup for a given locale.
  *
- * Returns: markup, or %NULL for not set or invalid
+ * Returns: (nullable): markup, or %NULL for not set or invalid
  **/
 const gchar*
 as_release_get_description (AsRelease *release)
@@ -512,7 +512,7 @@ as_release_get_checksums (AsRelease *release)
  *
  * Gets the release checksum
  *
- * Returns: (transfer none): an #AsChecksum, or %NULL for not set or invalid
+ * Returns: (transfer none) (nullable): an #AsChecksum, or %NULL for not set or invalid
  *
  * Since: 0.8.2
  **/
diff --git a/src/as-spdx.c b/src/as-spdx.c
index 500ae934..9c58e677 100644
--- a/src/as-spdx.c
+++ b/src/as-spdx.c
@@ -247,7 +247,7 @@ as_utils_spdx_license_3to2 (const gchar *license3)
  * with "|". Brackets are added as indervidual tokens and other strings are
  * appended into single tokens where possible.
  *
- * Returns: (transfer full): array of strings, or %NULL for invalid
+ * Returns: (transfer full) (nullable): array of strings, or %NULL for invalid
  *
  * Since: 0.9.8
  **/
@@ -302,7 +302,7 @@ as_spdx_license_tokenize (const gchar *license)
  *
  * De-tokenizes the SPDX licenses into a string.
  *
- * Returns: (transfer full): string, or %NULL for invalid
+ * Returns: (transfer full) (nullable): string, or %NULL for invalid
  *
  * Since: 0.9.8
  **/
diff --git a/src/as-utils.c b/src/as-utils.c
index f7aef5aa..da451c60 100644
--- a/src/as-utils.c
+++ b/src/as-utils.c
@@ -726,7 +726,7 @@ as_utils_locale_to_language (const gchar *locale)
  *
  * Finds a string in a pointer array.
  *
- * Returns: the const string, or %NULL if not found
+ * Returns: (nullable): the const string, or %NULL if not found
  **/
 const gchar*
 as_ptr_array_find_string (GPtrArray *array, const gchar *value)