diff --git a/ontology/CASE-develop.ttl b/ontology/CASE-develop.ttl
index 8a200e70..b51e735a 100644
--- a/ontology/CASE-develop.ttl
+++ b/ontology/CASE-develop.ttl
@@ -1056,6 +1056,8 @@ action:Action
 	rdfs:subClassOf core:UcoObject ;
 	rdfs:label "Action"@en ;
 	rdfs:comment "An action is something that may be done or performed."@en ;
+	rdfs:isDefinedBy <https://ontology.unifiedcyberontology.org/uco/types> ;
+	owl:disjointWith core:Event ;
 	sh:property
 		[
 			sh:class action:Action ;
@@ -1166,6 +1168,16 @@ action:Action
 	sh:targetClass action:Action ;
 	.
 
+action:Action-disjointWith-Event-shape
+	a sh:NodeShape ;
+	sh:message "action:Action and core:Event are disjoint classes."@en ;
+	sh:not [
+		a sh:NodeShape ;
+		sh:class core:Event ;
+	] ;
+	sh:targetClass action:Action ;
+	.
+
 action:ActionArgumentFacet
 	a
 		owl:Class ,
@@ -2061,6 +2073,7 @@ core:Event
 	rdfs:subClassOf core:UcoObject ;
 	rdfs:label "Event"@en ;
 	rdfs:comment "An Event is a noteworthy occurrence (something that happens or might happen)."@en ;
+	owl:disjointWith action:Action ;
 	sh:property
 		[
 			sh:class core:UcoObject ;