diff --git a/Changelog.md b/Changelog.md
index eea0f017f..2c46f09aa 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -4,6 +4,7 @@ Breaking changes:
  * ABI: remove the deprecated ``constant`` and ``payable`` fields.
  * ABI: the ``type`` field is now required and no longer specified to default to ``function``.
  * C API (``libsolc``): the provided callback now takes two parameters, kind and data. The callback can then be used for multiple purposes, such has file imports and SMT queries.
+ * C API (``libsolc``): Introduce context parameter.
  * Commandline interface: remove the text-based ast printer (``--ast``).
  * Command line interface: Switch to the new error reporter by default. ``--old-reporter`` falls back to the deprecated old error reporter.
  * Command line interface: Add option to disable or choose hash method between IPFS and Swarm for the bytecode metadata.
diff --git a/libsolc/libsolc.cpp b/libsolc/libsolc.cpp
index eba3aa7aa..ffe05eaef 100644
--- a/libsolc/libsolc.cpp
+++ b/libsolc/libsolc.cpp
@@ -38,7 +38,7 @@ using namespace solidity;
 namespace
 {
 
-ReadCallback::Callback wrapReadCallback(CStyleReadFileCallback _readCallback = nullptr)
+ReadCallback::Callback wrapReadCallback(CStyleReadFileCallback _readCallback, void* _readContext)
 {
 	ReadCallback::Callback readCallback;
 	if (_readCallback)
@@ -47,7 +47,7 @@ ReadCallback::Callback wrapReadCallback(CStyleReadFileCallback _readCallback = n
 		{
 			char* contents_c = nullptr;
 			char* error_c = nullptr;
-			_readCallback(_kind.c_str(), _data.c_str(), &contents_c, &error_c);
+			_readCallback(_readContext, _kind.c_str(), _data.c_str(), &contents_c, &error_c);
 			ReadCallback::Result result;
 			result.success = true;
 			if (!contents_c && !error_c)
@@ -73,9 +73,9 @@ ReadCallback::Callback wrapReadCallback(CStyleReadFileCallback _readCallback = n
 	return readCallback;
 }
 
-string compile(string _input, CStyleReadFileCallback _readCallback = nullptr)
+string compile(string _input, CStyleReadFileCallback _readCallback, void* _readContext)
 {
-	StandardCompiler compiler(wrapReadCallback(_readCallback));
+	StandardCompiler compiler(wrapReadCallback(_readCallback, _readContext));
 	return compiler.compile(std::move(_input));
 }
 
@@ -94,9 +94,9 @@ extern char const* solidity_version() noexcept
 {
 	return VersionString.c_str();
 }
-extern char const* solidity_compile(char const* _input, CStyleReadFileCallback _readCallback) noexcept
+extern char const* solidity_compile(char const* _input, CStyleReadFileCallback _readCallback, void* _readContext) noexcept
 {
-	s_outputBuffer = compile(_input, _readCallback);
+	s_outputBuffer = compile(_input, _readCallback, _readContext);
 	return s_outputBuffer.c_str();
 }
 extern void solidity_free() noexcept
diff --git a/libsolc/libsolc.h b/libsolc/libsolc.h
index ca7ded32b..22d43cba8 100644
--- a/libsolc/libsolc.h
+++ b/libsolc/libsolc.h
@@ -36,6 +36,7 @@ extern "C" {
 
 /// Callback used to retrieve additional source files or data.
 ///
+/// @param _context The readContext passed to solidity_compile. Can be NULL.
 /// @param _kind The kind of callback (a string).
 /// @param _data The data for the callback.
 /// @param o_contents A pointer to the contents of the file, if found.
@@ -44,7 +45,7 @@ extern "C" {
 /// If the callback is not supported, o_contents and o_error should be set to NULL.
 ///
 /// The two pointers (o_contents and o_error) should be heap-allocated and are free'd by the caller.
-typedef void (*CStyleReadFileCallback)(char const* _kind, char const* _data, char** o_contents, char** o_error);
+typedef void (*CStyleReadFileCallback)(void* _context, char const* _kind, char const* _data, char** o_contents, char** o_error);
 
 /// Returns the complete license document.
 ///
@@ -61,9 +62,10 @@ char const* solidity_version() SOLC_NOEXCEPT;
 ///
 /// @param _input The input JSON to process.
 /// @param _readCallback The optional callback pointer. Can be NULL.
+/// @param _readContext An optional context pointer passed to _readCallback. Can be NULL.
 ///
 /// @returns A pointer to the result. The pointer returned must not be freed by the caller.
-char const* solidity_compile(char const* _input, CStyleReadFileCallback _readCallback) SOLC_NOEXCEPT;
+char const* solidity_compile(char const* _input, CStyleReadFileCallback _readCallback, void* _readContext) SOLC_NOEXCEPT;
 
 /// Frees up any allocated memory.
 ///
diff --git a/test/externalTests/solc-js/solc-js.sh b/test/externalTests/solc-js/solc-js.sh
index daffee0e3..73d2d003b 100755
--- a/test/externalTests/solc-js/solc-js.sh
+++ b/test/externalTests/solc-js/solc-js.sh
@@ -35,7 +35,7 @@ function solcjs_test
     SOLCJS_INPUT_DIR="$TEST_DIR"/test/externalTests/solc-js
 
     # set up solc-js on the branch specified
-    setup master_060
+    setup callback-context
 
     printLog "Updating index.js file..."
     echo "require('./determinism.js');" >> test/index.js
diff --git a/test/libsolidity/LibSolc.cpp b/test/libsolidity/LibSolc.cpp
index 7beebf3ea..e2a208273 100644
--- a/test/libsolidity/LibSolc.cpp
+++ b/test/libsolidity/LibSolc.cpp
@@ -59,7 +59,7 @@ bool containsError(Json::Value const& _compilerResult, string const& _type, stri
 
 Json::Value compile(string const& _input, CStyleReadFileCallback _callback = nullptr)
 {
-	string output(solidity_compile(_input.c_str(), _callback));
+	string output(solidity_compile(_input.c_str(), _callback, nullptr));
 	Json::Value ret;
 	BOOST_REQUIRE(jsonParseStrict(output, ret));
 	solidity_free();
@@ -138,8 +138,10 @@ BOOST_AUTO_TEST_CASE(with_callback)
 	)";
 
 	CStyleReadFileCallback callback{
-		[](char const* _kind, char const* _path, char** o_contents, char** o_error)
+		[](void* _context, char const* _kind, char const* _path, char** o_contents, char** o_error)
 		{
+			// Passed in a nullptr in the compile() helper above.
+			BOOST_CHECK(_context == nullptr);
 			// Caller frees the pointers.
 			BOOST_CHECK(string(_kind) == ReadCallback::kindString(ReadCallback::Kind::ReadFile));
 			if (string(_path) == "found.sol")
diff --git a/test/tools/fuzzer_common.cpp b/test/tools/fuzzer_common.cpp
index 5cd64a6c7..ba97545bc 100644
--- a/test/tools/fuzzer_common.cpp
+++ b/test/tools/fuzzer_common.cpp
@@ -42,7 +42,7 @@ void FuzzerUtil::runCompiler(string const& _input, bool _quiet)
 {
 	if (!_quiet)
 		cout << "Input JSON: " << _input << endl;
-	string outputString(solidity_compile(_input.c_str(), nullptr));
+	string outputString(solidity_compile(_input.c_str(), nullptr, nullptr));
 	if (!_quiet)
 		cout << "Output JSON: " << outputString << endl;