diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index 25702f194..567356984 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -2429,7 +2429,7 @@ FunctionType::FunctionType(VariableDeclaration const& _varDecl):
 		else if (auto arrayType = dynamic_cast<ArrayType const*>(returnType.get()))
 		{
 			if (arrayType->isByteArray())
-				// Return byte arrays as as whole.
+				// Return byte arrays as whole.
 				break;
 			returnType = arrayType->baseType();
 			m_parameterNames.push_back("");
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index 65a70019c..0f3373a1f 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -174,7 +174,7 @@ public:
 	/// Will not contain any character which would be invalid as an identifier.
 	std::string identifier() const;
 
-	/// More complex identifier strings use "parentheses", where $_ is interpreted as as
+	/// More complex identifier strings use "parentheses", where $_ is interpreted as
 	/// "opening parenthesis", _$ as "closing parenthesis", _$_ as "comma" and any $ that
 	/// appears as part of a user-supplied identifier is escaped as _$$$_.
 	/// @returns an escaped identifier (will not contain any parenthesis or commas)
diff --git a/libsolidity/codegen/ExpressionCompiler.cpp b/libsolidity/codegen/ExpressionCompiler.cpp
index 8645f653c..587cf34a1 100644
--- a/libsolidity/codegen/ExpressionCompiler.cpp
+++ b/libsolidity/codegen/ExpressionCompiler.cpp
@@ -1230,7 +1230,7 @@ bool ExpressionCompiler::visit(MemberAccess const& _memberAccess)
 						else
 							solAssert(false, "Contract member is neither variable nor function.");
 						m_context << identifier;
-						/// need to store store it as bytes4
+						/// need to store it as bytes4
 						utils().leftShiftNumberOnStack(224);
 						return false;
 					}
@@ -1305,7 +1305,7 @@ bool ExpressionCompiler::visit(MemberAccess const& _memberAccess)
 		if (member == "selector")
 		{
 			m_context << Instruction::SWAP1 << Instruction::POP;
-			/// need to store store it as bytes4
+			/// need to store it as bytes4
 			utils().leftShiftNumberOnStack(224);
 		}
 		else
@@ -1975,7 +1975,7 @@ void ExpressionCompiler::appendExternalFunctionCall(
 	m_context << dupInstruction(m_context.baseToCurrentStackOffset(contractStackPos));
 
 	bool existenceChecked = false;
-	// Check the the target contract exists (has code) for non-low-level calls.
+	// Check the target contract exists (has code) for non-low-level calls.
 	if (funKind == FunctionType::Kind::External || funKind == FunctionType::Kind::DelegateCall)
 	{
 		m_context << Instruction::DUP1 << Instruction::EXTCODESIZE << Instruction::ISZERO;
diff --git a/libsolidity/inlineasm/AsmCodeGen.h b/libsolidity/inlineasm/AsmCodeGen.h
index a7d7ead1a..277e18790 100644
--- a/libsolidity/inlineasm/AsmCodeGen.h
+++ b/libsolidity/inlineasm/AsmCodeGen.h
@@ -41,7 +41,7 @@ struct Block;
 class CodeGenerator
 {
 public:
-	/// Performs code generation and appends generated to to _assembly.
+	/// Performs code generation and appends generated to _assembly.
 	static void assemble(
 		Block const& _parsedData,
 		AsmAnalysisInfo& _analysisInfo,