diff --git a/include/sirit/sirit.h b/include/sirit/sirit.h
index f8646b6..253e152 100644
--- a/include/sirit/sirit.h
+++ b/include/sirit/sirit.h
@@ -50,6 +50,10 @@ class Module {
                        const std::string& name,
                        const std::vector<Id>& interfaces = {});
 
+    /// Declare an execution mode for an entry point.
+    void AddExecutionMode(Id entry_point, spv::ExecutionMode mode,
+                          const std::vector<Literal>& literals = {});
+
     /**
      * Adds an instruction to module's code
      * @param op Instruction to insert into code. Types and constants must not
@@ -619,7 +623,7 @@ class Module {
     spv::MemoryModel memory_model{spv::MemoryModel::GLSL450};
 
     std::vector<std::unique_ptr<Op>> entry_points;
-    std::vector<std::unique_ptr<Op>> execution_mode;
+    std::vector<std::unique_ptr<Op>> execution_modes;
     std::vector<std::unique_ptr<Op>> debug;
     std::vector<std::unique_ptr<Op>> annotations;
     std::vector<std::unique_ptr<Op>> declarations;
diff --git a/src/sirit.cpp b/src/sirit.cpp
index 89df604..e03fcdf 100644
--- a/src/sirit.cpp
+++ b/src/sirit.cpp
@@ -49,7 +49,7 @@ std::vector<u8> Module::Assemble() const {
     memory_model_ref.Write(stream);
 
     WriteSet(stream, entry_points);
-    // TODO write execution mode
+    WriteSet(stream, execution_modes);
     WriteSet(stream, debug);
     WriteSet(stream, annotations);
     WriteSet(stream, declarations);
@@ -80,6 +80,15 @@ void Module::AddEntryPoint(spv::ExecutionModel execution_model, Id entry_point,
     entry_points.push_back(std::move(op));
 }
 
+void Module::AddExecutionMode(Id entry_point, spv::ExecutionMode mode,
+    const std::vector<Literal>& literals) {
+    auto op{std::make_unique<Op>(spv::Op::OpExecutionMode)};
+    op->Add(entry_point);
+    op->Add(static_cast<u32>(mode));
+    op->Add(literals);
+    execution_modes.push_back(std::move(op));
+}
+
 Id Module::Emit(Id op) {
     code.push_back(op);
     return op;