diff --git a/src/plasp/pddl/expressions/Not.cpp b/src/plasp/pddl/expressions/Not.cpp
index fec4f57..72efe5b 100644
--- a/src/plasp/pddl/expressions/Not.cpp
+++ b/src/plasp/pddl/expressions/Not.cpp
@@ -47,6 +47,14 @@ ExpressionPointer Not::normalize()
 {
 	BOOST_ASSERT(m_argumentStorage);
 
+	// Remove double negations
+	if (m_argumentStorage->expressionType() == Expression::Type::Not)
+	{
+		auto &argument = dynamic_cast<Not &>(*m_argumentStorage);
+
+		return std::move(argument.m_argumentStorage);
+	}
+
 	auto normalizedArgument = m_argumentStorage->normalize();
 
 	// Replace argument if changed by normalization