diff --git a/meta/classes/create-spdx-2.2.bbclass b/meta/classes/create-spdx-2.2.bbclass
index 28a42e009f6..8b18ada40a4 100644
--- a/meta/classes/create-spdx-2.2.bbclass
+++ b/meta/classes/create-spdx-2.2.bbclass
@@ -484,7 +484,10 @@ python do_create_spdx() {
 
     if d.getVar("SPDX_CUSTOM_ANNOTATION_VARS"):
         for var in d.getVar('SPDX_CUSTOM_ANNOTATION_VARS').split():
-            recipe.annotations.append(create_annotation(d, var + "=" + d.getVar(var)))
+            if d.getVar(var):
+                recipe.annotations.append(create_annotation(d, var + "= '" + d.getVar(var) + "'"))
+            else:
+                recipe.annotations.append(create_annotation(d, var + "=''"))
 
     # Some CVEs may be patched during the build process without incrementing the version number,
     # so querying for CVEs based on the CPE id can lead to false positives. To account for this,