diff --git a/reqif/parsers/spec_types/relation_group_type_parser.py b/reqif/parsers/spec_types/relation_group_type_parser.py
index 3b6b165..d2bd843 100644
--- a/reqif/parsers/spec_types/relation_group_type_parser.py
+++ b/reqif/parsers/spec_types/relation_group_type_parser.py
@@ -55,7 +55,11 @@ def unparse(spec_relation_type: ReqIFRelationGroupType):
             output += f' LAST-CHANGE="{spec_relation_type.last_change}"'
         if spec_relation_type.long_name is not None:
             output += f' LONG-NAME="{spec_relation_type.long_name}"'
-        if spec_relation_type.is_self_closed:
+        has_attributes = (
+            spec_relation_type.attribute_definitions is not None
+            and len(spec_relation_type.attribute_definitions) > 0
+        )
+        if spec_relation_type.is_self_closed and not has_attributes:
             output += "/>\n"
             return output
 
diff --git a/reqif/parsers/spec_types/spec_relation_type_parser.py b/reqif/parsers/spec_types/spec_relation_type_parser.py
index 92a8a11..f31cc18 100644
--- a/reqif/parsers/spec_types/spec_relation_type_parser.py
+++ b/reqif/parsers/spec_types/spec_relation_type_parser.py
@@ -52,7 +52,11 @@ def unparse(spec_relation_type: ReqIFSpecRelationType):
             output += f' LAST-CHANGE="{spec_relation_type.last_change}"'
         if spec_relation_type.long_name is not None:
             output += f' LONG-NAME="{spec_relation_type.long_name}"'
-        if spec_relation_type.is_self_closed:
+        has_attributes = (
+            spec_relation_type.attribute_definitions is not None
+            and len(spec_relation_type.attribute_definitions) > 0
+        )
+        if spec_relation_type.is_self_closed and not has_attributes:
             output += "/>\n"
             return output
 
diff --git a/reqif/parsers/spec_types/specification_type_parser.py b/reqif/parsers/spec_types/specification_type_parser.py
index de1684c..538ea6a 100644
--- a/reqif/parsers/spec_types/specification_type_parser.py
+++ b/reqif/parsers/spec_types/specification_type_parser.py
@@ -67,7 +67,10 @@ def unparse(spec_type: ReqIFSpecificationType) -> str:
             output += f' LONG-NAME="{spec_type.long_name}"'
 
         # Some documents have a SPECIFICATION-TYPE without any SPEC-ATTRIBUTES.
-        if spec_type.is_self_closed:
+        has_attributes = (
+            spec_type.spec_attributes is not None and len(spec_type.spec_attributes) > 0
+        )
+        if spec_type.is_self_closed and not has_attributes:
             output += "/>\n"
             return output
         else: