diff --git a/CMakeLists.txt b/CMakeLists.txt
index 09eef57a9..7913af7d7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -251,6 +251,7 @@ file(GLOB_RECURSE STORM_SETTINGS_FILES ${PROJECT_SOURCE_DIR}/src/settings/*.h ${
 file(GLOB_RECURSE STORM_SOLVER_FILES ${PROJECT_SOURCE_DIR}/src/solver/*.h ${PROJECT_SOURCE_DIR}/src/solver/*.cpp)
 file(GLOB STORM_STORAGE_FILES ${PROJECT_SOURCE_DIR}/src/storage/*.h ${PROJECT_SOURCE_DIR}/src/storage/*.cpp)
 file(GLOB_RECURSE STORM_STORAGE_DD_FILES ${PROJECT_SOURCE_DIR}/src/storage/dd/*.h ${PROJECT_SOURCE_DIR}/src/storage/dd/*.cpp)
+file(GLOB_RECURSE STORM_STORAGE_EXPRESSIONS_FILES ${PROJECT_SOURCE_DIR}/src/storage/expressions/*.h ${PROJECT_SOURCE_DIR}/src/storage/expressions/*.cpp)
 file(GLOB_RECURSE STORM_UTILITY_FILES ${PROJECT_SOURCE_DIR}/src/utility/*.h ${PROJECT_SOURCE_DIR}/src/utility/*.cpp)
 file(GLOB STORM_IR_FILES ${PROJECT_SOURCE_DIR}/src/ir/*.h ${PROJECT_SOURCE_DIR}/src/ir/*.cpp)
 file(GLOB_RECURSE STORM_IR_EXPRESSIONS_FILES ${PROJECT_SOURCE_DIR}/src/ir/expressions/*.h ${PROJECT_SOURCE_DIR}/src/ir/expressions/*.cpp)
@@ -284,6 +285,7 @@ source_group(settings FILES ${STORM_SETTINGS_FILES})
 source_group(solver FILES ${STORM_SOLVER_FILES})
 source_group(storage FILES ${STORM_STORAGE_FILES})
 source_group(storage\\dd FILES ${STORM_STORAGE_DD_FILES})
+source_group(storage\\expressions FILES ${STORM_STORAGE_EXPRESSIONS_FILES})
 source_group(utility FILES ${STORM_UTILITY_FILES})
 source_group(functional-test FILES ${STORM_FUNCTIONAL_TEST_FILES})
 source_group(performance-test FILES ${STORM_PERFORMANCE_TEST_FILES})
diff --git a/src/storage/expressions/BaseExpression.h b/src/storage/expressions/BaseExpression.h
new file mode 100644
index 000000000..85b521726
--- /dev/null
+++ b/src/storage/expressions/BaseExpression.h
@@ -0,0 +1,26 @@
+#ifndef STORM_STORAGE_EXPRESSIONS_BASEEXPRESSION_H_
+#define STORM_STORAGE_EXPRESSIONS_BASEEXPRESSION_H_
+
+#include "src/storage/expressions/Valuation.h"
+
+namespace storm {
+    namespace expressions {
+        class BaseExpression {
+        public:
+            /*!
+             * Each node in an expression tree has a uniquely defined type from this enum.
+             */
+            enum ReturnType {undefined, bool_, int_, double_};
+            
+            std::unique_ptr<BaseExpression> substitute() const = 0;
+            
+            virtual int_fast64_t evaluateAsInt(Evaluation const& evaluation) const = 0;
+            
+            virtual bool evaluateAsBool(Evaluation const& evaluation) const = 0;
+            
+            virtual double evaluateAsDouble(Evaluation const& evaluation) const = 0;
+        };
+    }
+}
+
+#endif /* STORM_STORAGE_EXPRESSIONS_BASEEXPRESSION_H_ */
\ No newline at end of file
diff --git a/src/storage/expressions/Expression.cpp b/src/storage/expressions/Expression.cpp
new file mode 100644
index 000000000..335fa3ca7
--- /dev/null
+++ b/src/storage/expressions/Expression.cpp
@@ -0,0 +1,13 @@
+#include "src/storage/expressions/Expression.h"
+
+namespace storm {
+    namespace expressions {
+        virtual Expression Expression::operator+(Expression const& other) {
+            return Expression(this->getBaseExpression() + other.getBaseExpression());
+        }
+        
+        BaseExpression const& getBaseExpression() const {
+            return *this->expressionPtr;
+        }
+    }
+}
diff --git a/src/storage/expressions/Expression.h b/src/storage/expressions/Expression.h
new file mode 100644
index 000000000..c44219736
--- /dev/null
+++ b/src/storage/expressions/Expression.h
@@ -0,0 +1,42 @@
+#ifndef STORM_STORAGE_EXPRESSIONS_EXPRESSION_H_
+#define STORM_STORAGE_EXPRESSIONS_EXPRESSION_H_
+
+namespace storm {
+    namespace expressions {
+        class Expression {
+            Expression() = default;
+            
+            // Static factory methods to create atomic expression parts.
+            
+            // Virtual operator overloading.
+            virtual Expression operator+(Expression const& other);
+            
+            /*!
+             * Substitutes all occurrences of identifiers according to the given substitution. Note that this
+             * substitution is done simultaneously, i.e., identifiers appearing in the expressions that were "plugged
+             * in" are not substituted.
+             *
+             * @param substitutionFilter A function that returns true iff the given identifier is supposed to be
+             * substituted.
+             * @param substitution A substitution that returns for each identifier an expression that is supposed to
+             * replace the identifier.
+             * @return An expression in which all identifiers
+             */
+            Expression substitute(std::function<Expression (std::string const&)> const& substitution) const;
+            
+        private:
+            /*!
+             * Retrieves the base expression underlying this expression object. Note that prior to calling this, the
+             * expression object must be properly initialized.
+             *
+             * @return A reference to the underlying base expression.
+             */
+            BaseExpression const& getBaseExpression() const;
+            
+            // A pointer to the underlying base expression.
+            std::unique_ptr<BaseExpression> expressionPtr;
+        };
+    }
+}
+
+#endif /* STORM_STORAGE_EXPRESSIONS_EXPRESSION_H_ */
\ No newline at end of file
diff --git a/src/storage/expressions/SimpleValuation.cpp b/src/storage/expressions/SimpleValuation.cpp
new file mode 100644
index 000000000..20c9f9f2f
--- /dev/null
+++ b/src/storage/expressions/SimpleValuation.cpp
@@ -0,0 +1,29 @@
+#include "src/storage/expressions/SimpleValuation.h"
+
+namespace storm {
+    namespace expressions {
+        SimpleValuation::SimpleValuation(std::size_t booleanVariableCount, std::size_t integerVariableCount, std::size_t doubleVariableCount) : identifierToIndexMap(), booleanValues(booleanVariableCount), integerValues(integerVariableCount), doubleValues(doubleVariableCount) {
+            // Intentionally left empty.
+        }
+        
+        SimpleValuation::SimpleValuation(std::shared_ptr<std::unordered_map<std::string, uint_fast64_t>> identifierToIndexMap, std::vector<bool> booleanValues, std::vector<int_fast64_t> integerValues, std::vector<double> doubleValues) : identifierToIndexMap(identifierToIndexMap), booleanValues(booleanValues), integerValues(integerValues), doubleValues(doubleValues) {
+            // Intentionally left empty.
+        }
+
+        void SimpleValuation::setIdentifierIndex(std::string const& name, uint_fast64_t index) {
+            (*this->identifierToIndexMap)[name] = index;
+        }
+        
+        bool SimpleValuation::getBooleanValue(std::string const& name) const {
+            return false;
+        }
+        
+        int_fast64_t SimpleValuation::getIntegerValue(std::string const& name) const {
+            return 0;
+        }
+        
+        double SimpleValuation::getDoubleValue(std::string const& name) const {
+            return 0.0;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/storage/expressions/SimpleValuation.h b/src/storage/expressions/SimpleValuation.h
new file mode 100644
index 000000000..fd7d3c8b0
--- /dev/null
+++ b/src/storage/expressions/SimpleValuation.h
@@ -0,0 +1,40 @@
+#ifndef STORM_STORAGE_EXPRESSIONS_SIMPLEVALUATION_H_
+#define STORM_STORAGE_EXPRESSIONS_SIMPLEVALUATION_H_
+
+#include <memory>
+#include <vector>
+#include <string>
+#include <unordered_map>
+
+#include "src/storage/expressions/Valuation.h"
+
+namespace storm {
+    namespace expressions {
+        class SimpleValuation : public Valuation {
+        public:
+            SimpleValuation(std::size_t booleanVariableCount, std::size_t integerVariableCount, std::size_t doubleVariableCount);
+            
+            SimpleValuation(std::shared_ptr<std::unordered_map<std::string, uint_fast64_t>> identifierToIndexMap, std::vector<bool> booleanValues, std::vector<int_fast64_t> integerValues, std::vector<double> doubleValues);
+
+            SimpleValuation() = default;
+            SimpleValuation(SimpleValuation const&) = default;
+            SimpleValuation(SimpleValuation&&) = default;
+            SimpleValuation& operator=(SimpleValuation const&) = default;
+            SimpleValuation& operator=(SimpleValuation&&) = default;
+            
+            void setIdentifierIndex(std::string const& name, uint_fast64_t index);
+            
+            virtual bool getBooleanValue(std::string const& name) const override;
+            virtual int_fast64_t getIntegerValue(std::string const& name) const override;
+            virtual double getDoubleValue(std::string const& name) const override;
+            
+        private:
+            std::shared_ptr<std::unordered_map<std::string, uint_fast64_t>> identifierToIndexMap;
+            std::vector<bool> booleanValues;
+            std::vector<int_fast64_t> integerValues;
+            std::vector<double> doubleValues;
+        };
+    }
+}
+
+#endif /* STORM_STORAGE_EXPRESSIONS_SIMPLEVALUATION_H_ */
\ No newline at end of file
diff --git a/src/storage/expressions/Valuation.h b/src/storage/expressions/Valuation.h
new file mode 100644
index 000000000..c2d0b01cb
--- /dev/null
+++ b/src/storage/expressions/Valuation.h
@@ -0,0 +1,15 @@
+#ifndef STORM_STORAGE_EXPRESSIONS_VALUATION_H_
+#define STORM_STORAGE_EXPRESSIONS_VALUATION_H_
+
+namespace storm {
+    namespace expressions {
+        class Valuation {
+        public:
+            virtual bool getBooleanValue(std::string const& name) const = 0;
+            virtual int_fast64_t getIntegerValue(std::string const& name) const = 0;
+            virtual double getDoubleValue(std::string const& name) const = 0;
+        };
+    }
+}
+
+#endif /* STORM_STORAGE_EXPRESSIONS_VALUATION_H_ */
\ No newline at end of file
diff --git a/test/functional/storage/ExpressionTest.cpp b/test/functional/storage/ExpressionTest.cpp
new file mode 100644
index 000000000..9d9307bea
--- /dev/null
+++ b/test/functional/storage/ExpressionTest.cpp
@@ -0,0 +1,9 @@
+#include "gtest/gtest.h"
+
+#include <map>
+
+#include "src/storage/expressions/SimpleValuation.h"
+
+TEST(Expression, SimpleValuationTest) {
+    ASSERT_NO_THROW(storm::expressions::SimpleValuation evaluation(1, 1, 1));
+}
\ No newline at end of file