diff --git a/tests/test_OWLObjectComplementOf.py b/tests/test_OWLObjectComplementOf.py
new file mode 100644
index 0000000..50c6131
--- /dev/null
+++ b/tests/test_OWLObjectComplementOf.py
@@ -0,0 +1,40 @@
+from owlapy.class_expression import (
+    OWLClass,
+    OWLObjectComplementOf,
+)
+from owlapy.iri import IRI
+from owlapy.owl_reasoner import SyncReasoner
+from owlapy.owl_ontology_manager import SyncOntologyManager
+
+def test_complement_of_owl_thing_is_owl_nothing():
+    owl_thing = OWLClass(IRI.create('http://www.w3.org/2002/07/owl#Thing'))
+    owl_nothing = OWLClass(IRI.create('http://www.w3.org/2002/07/owl#Nothing'))
+    complement_of_thing = OWLObjectComplementOf(owl_thing)
+    complement_of_nothing = OWLObjectComplementOf(owl_nothing)
+    mgr = SyncOntologyManager()
+    onto = mgr.load_ontology("KGs/Mutagenesis/mutagenesis.owl")
+    reasoner = SyncReasoner(onto, "HermiT")
+    equivalent_classes = reasoner.equivalent_classes(complement_of_thing)
+    assert owl_nothing in equivalent_classes
+    individuals_thing = reasoner.instances(owl_thing)
+    individuals_complement_of_nothing = reasoner.instances(complement_of_nothing)
+    assert individuals_thing == individuals_complement_of_nothing
+
+def test_complement_of_owl_nothing_is_owl_thing():
+    owl_thing = OWLClass(IRI.create('http://www.w3.org/2002/07/owl#Thing'))
+    owl_nothing = OWLClass(IRI.create('http://www.w3.org/2002/07/owl#Nothing'))
+    complement_of_nothing = OWLObjectComplementOf(owl_nothing)
+    mgr = SyncOntologyManager()
+    onto = mgr.load_ontology("KGs/Mutagenesis/mutagenesis.owl")
+    reasoner = SyncReasoner(onto, "HermiT")
+    individuals_thing = reasoner.instances(owl_thing)
+    individuals_complement_of_nothing = reasoner.instances(complement_of_nothing)
+    assert individuals_thing == individuals_complement_of_nothing
+
+def test_double_complement_is_identity():
+    class_iri = IRI.create('http://example.org/MyClass')
+    my_class = OWLClass(class_iri)
+    complement = OWLObjectComplementOf(my_class)
+    double_complement = OWLObjectComplementOf(complement)
+    assert my_class == double_complement
+