diff --git a/Changes.md b/Changes.md
index 4c749ceafaf..f077bac68da 100644
--- a/Changes.md
+++ b/Changes.md
@@ -19,6 +19,7 @@ Fixes
 - Arnold :
   - Fixed rendering of shaders imported from HtoA via USD.
   - Fixed USD export of shaders to use `outputs:out` instead of `outputs:DEFAULT_OUTPUT`.
+  - Fixed rendering of `osl` shaders using the `code` parameter.
 - GafferTest, GafferImageTest : Fixed import of these modules if the `Gaffer` module had not been imported previously.
 - SceneAlgo : Fixed potential shutdown crashes caused by the adaptor registry [^1].
 - Dispatcher : Fixed shutdown crashes caused by Python slots connected to the dispatch signals [^1].
diff --git a/python/IECoreArnoldTest/RendererTest.py b/python/IECoreArnoldTest/RendererTest.py
index 46a065defca..a8f637fc15d 100644
--- a/python/IECoreArnoldTest/RendererTest.py
+++ b/python/IECoreArnoldTest/RendererTest.py
@@ -4254,6 +4254,60 @@ def testOSLOutParameter( self ) :
 			input = arnold.AiNodeGetLink( surfaceShader, "base_color" )
 			self.assertIn( "colorSwitch", arnold.AiNodeGetName( input ) )
 
+	def testArnoldOSLWithCode( self ) :
+
+		renderer = GafferScene.Private.IECoreScenePreview.Renderer.create(
+			"Arnold",
+			GafferScene.Private.IECoreScenePreview.Renderer.RenderType.Batch
+		)
+
+		# This test exercises a problem that would occur if we tried to set
+		# Arnold's `param_*` attributes before setting the `code` attribute.
+		# Due to InternedString ordering rules, the likelihood of visiting the
+		# parameters in that order is increased by constructing the `param_colorIn`
+		# string first.
+		IECore.InternedString( "param_colorIn" )
+
+		renderer.object(
+			"testPlane",
+			IECoreScene.MeshPrimitive.createPlane( imath.Box2f( imath.V2f( -1 ), imath.V2f( 1 ) ) ),
+			renderer.attributes( IECore.CompoundObject( {
+				"ai:surface" : IECoreScene.ShaderNetwork(
+					shaders = {
+						"osl" : IECoreScene.Shader(
+							"osl", "ai:shader",
+							{
+								"code" : """
+									shader myConstant(
+										color colorIn = 0,
+										output color colorOut = 0
+									)
+									{
+										colorOut = colorIn;
+									}
+								""",
+								"param_colorIn" : imath.Color3f( 0, 1, 0 ),
+							}
+						),
+					},
+					output = "osl"
+				)
+			} ) ),
+		)
+
+		universe = ctypes.cast( renderer.command( "ai:queryUniverse", {} ), ctypes.POINTER( arnold.AtUniverse ) )
+
+		shader = arnold.AiNodeGetPtr( arnold.AiNodeLookUpByName( universe, "testPlane" ), "shader" )
+		self.assertEqual( arnold.AiNodeEntryGetName( arnold.AiNodeGetNodeEntry(  shader ) ), "osl" )
+
+		# If we have set things in the right order, then `param_colorIn` will exist and have the right value.
+		self.assertEqual( arnold.AiNodeGetRGB( shader, "param_colorIn" ), arnold.AtRGB( 0, 1, 0 ) )
+		# And it won't have been declared as a user parameter, because setting `code` declares it as a built-in
+		# parameter instead.
+		self.assertIsNone( arnold.AiNodeLookUpUserParameter( shader, "param_colorIn" ) )
+
+		del renderer
+
 	def testInternedStringAttributes( self ) :
 
 		r = GafferScene.Private.IECoreScenePreview.Renderer.create(
diff --git a/src/IECoreArnold/ShaderNetworkAlgo.cpp b/src/IECoreArnold/ShaderNetworkAlgo.cpp
index 33e18e1ffdf..f4ae09c14e6 100644
--- a/src/IECoreArnold/ShaderNetworkAlgo.cpp
+++ b/src/IECoreArnold/ShaderNetworkAlgo.cpp
@@ -62,6 +62,7 @@ using namespace IECoreArnold;
 namespace
 {
 
+const AtString g_codeArnoldString( "code" );
 const AtString g_emptyArnoldString( "" );
 const AtString g_outputArnoldString( "output" );
 const AtString g_shaderNameArnoldString( "shadername" );
@@ -109,6 +110,19 @@ AtNode *convertWalk( const ShaderNetwork::Parameter &outputParameter, const IECo
 			AtString( shader->getName().c_str() ),
 			AtString( nodeName.c_str() )
 		);
+		if( node && AiNodeEntryGetNameAtString( AiNodeGetNodeEntry( node ) ) == g_oslArnoldString )
+		{
+			// Need to set the `code` parameter on `osl` shaders _before_ we try to set
+			// the other parameters, because otherwise they don't exist yet.
+			// Note : This code path is different to the `isOSLShader` one. This code path
+			// deals with shaders authored explicitly to use Arnold's `osl` shader node (which
+			// therefore wouldn't work in other renderers). The `isOSLShader` code path deals
+			// with generically-authored OSL shaders that we are translating to Arnold.
+			if( auto *code = shader->parametersData()->member<StringData>( "code" ) )
+			{
+				AiNodeSetStr( node, g_codeArnoldString, AtString( code->readable().c_str() ) );
+			}
+		}
 	}
 
 	if( !node )