diff --git a/include/plasp/pddl/translation/Effect.h b/include/plasp/pddl/translation/Effect.h
index a8f7c8e..9b212fb 100644
--- a/include/plasp/pddl/translation/Effect.h
+++ b/include/plasp/pddl/translation/Effect.h
@@ -9,6 +9,8 @@
 
 #include <plasp/pddl/translation/Predicate.h>
 #include <plasp/pddl/translation/Primitives.h>
+#include <plasp/pddl/translation/Variables.h>
+#include <plasp/pddl/translation/VariableStack.h>
 
 namespace plasp
 {
@@ -22,7 +24,7 @@ namespace pddl
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
 template<typename PrintObjectName>
-inline void translateEffect(colorlog::ColorStream &outputStream, const ::pddl::normalizedAST::Effect &effect, const std::string &objectType, PrintObjectName printObjectName)
+inline void translateEffect(colorlog::ColorStream &outputStream, const ::pddl::normalizedAST::Effect &effect, const std::string &objectType, PrintObjectName printObjectName, VariableStack &variableStack)
 {
 	const auto handlePredicate =
 		[&](const ::pddl::normalizedAST::PredicatePointer &predicate, bool isPositive = true)
@@ -36,13 +38,37 @@ inline void translateEffect(colorlog::ColorStream &outputStream, const ::pddl::n
 			translatePredicateToVariable(outputStream, *predicate, isPositive);
 			outputStream << ") :- " << colorlog::Function(objectType.c_str()) << "(";
 			printObjectName();
-			outputStream << ").";
+			outputStream << ")";
+
+			if (!variableStack.layers.empty())
+				for (const auto &layer : variableStack.layers)
+				{
+					if (!layer->empty())
+						outputStream << ", ";
+
+					translateVariablesForRuleBody(outputStream, *layer);
+				}
+
+			outputStream << ".";
+		};
+
+	const auto handleNegatedPredicate =
+		[&](const ::pddl::normalizedAST::PredicatePointer &predicate)
+		{
+			handlePredicate(predicate, false);
 		};
 
 	const auto handleDerivedPredicate =
 		[&](const ::pddl::normalizedAST::DerivedPredicatePointer &, bool = true)
 		{
-			throw TranslatorException("derived predicates not yet supported by translator");
+			// TODO: refactor as to exclude derived predicates from the Effect variant
+			throw TranslatorException("derived predicates should not appear in effects");
+		};
+
+	const auto handleNegatedDerivedPredicate =
+		[&](const ::pddl::normalizedAST::DerivedPredicatePointer &derivedPredicate)
+		{
+			handleDerivedPredicate(derivedPredicate, false);
 		};
 
 	const auto handleAtomicFormula =
@@ -54,12 +80,7 @@ inline void translateEffect(colorlog::ColorStream &outputStream, const ::pddl::n
 	const auto handleNot =
 		[&](const ::pddl::normalizedAST::NotPointer<::pddl::normalizedAST::AtomicFormula> &not_)
 		{
-			if (!not_->argument.is<::pddl::normalizedAST::PredicatePointer>())
-				throw TranslatorException("only “and” expressions and (negated) predicates supported as action effects currently");
-
-			const auto &predicate = not_->argument.get<::pddl::normalizedAST::PredicatePointer>();
-
-			handlePredicate(predicate, false);
+			not_->argument.match(handleNegatedPredicate, handleNegatedDerivedPredicate);
 		};
 
 	const auto handleLiteral =
@@ -72,13 +93,17 @@ inline void translateEffect(colorlog::ColorStream &outputStream, const ::pddl::n
 		[&](const ::pddl::normalizedAST::AndPointer<::pddl::normalizedAST::Effect> &and_)
 		{
 			for (const auto &argument : and_->arguments)
-				translateEffect(outputStream, argument, objectType, printObjectName);
+				translateEffect(outputStream, argument, objectType, printObjectName, variableStack);
 		};
 
 	const auto handleForAll =
-		[&](const ::pddl::normalizedAST::ForAllPointer<::pddl::normalizedAST::Effect> &)
+		[&](const ::pddl::normalizedAST::ForAllPointer<::pddl::normalizedAST::Effect> &forAll)
 		{
-			throw TranslatorException("“when” expressions not yet supported by translator");
+			variableStack.push(&forAll->parameters);
+
+			translateEffect(outputStream, forAll->argument, objectType, printObjectName, variableStack);
+
+			variableStack.pop();
 		};
 
 	const auto handleWhen =
@@ -92,6 +117,16 @@ inline void translateEffect(colorlog::ColorStream &outputStream, const ::pddl::n
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 
+template<typename PrintObjectName>
+inline void translateEffect(colorlog::ColorStream &outputStream, const ::pddl::normalizedAST::Effect &effect, const std::string &objectType, PrintObjectName printObjectName)
+{
+	VariableStack variableStack;
+
+	translateEffect(outputStream, effect, objectType, printObjectName, variableStack);
+}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
 }
 }
 
diff --git a/include/plasp/pddl/translation/VariableStack.h b/include/plasp/pddl/translation/VariableStack.h
new file mode 100644
index 0000000..e3b8e0d
--- /dev/null
+++ b/include/plasp/pddl/translation/VariableStack.h
@@ -0,0 +1,39 @@
+#ifndef __PLASP__PDDL__TRANSLATION__VARIABLE_STACK_H
+#define __PLASP__PDDL__TRANSLATION__VARIABLE_STACK_H
+
+#include <pddlparse/NormalizedAST.h>
+
+namespace plasp
+{
+namespace pddl
+{
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+//
+// VariableStack
+//
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+struct VariableStack
+{
+	using Layer = ::pddl::normalizedAST::VariableDeclarations *;
+
+	void push(Layer layer)
+	{
+		layers.push_back(layer);
+	}
+
+	void pop()
+	{
+		layers.pop_back();
+	}
+
+	std::vector<Layer> layers;
+};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////
+
+}
+}
+
+#endif
diff --git a/src/plasp/pddl/TranslatorASP.cpp b/src/plasp/pddl/TranslatorASP.cpp
index 270f415..0722984 100644
--- a/src/plasp/pddl/TranslatorASP.cpp
+++ b/src/plasp/pddl/TranslatorASP.cpp
@@ -337,6 +337,7 @@ void TranslatorASP::translateActions() const
 		if (action->precondition)
 			translatePrecondition(m_outputStream, action->precondition.value(), "action", printActionName);
 
+		// Effect
 		if (action->effect)
 			translateEffect(m_outputStream, action->effect.value(), "action", printActionName);