diff --git a/source/MaterialXGenMdl/mdl/materialx/stdlib_1_6.mdl b/source/MaterialXGenMdl/mdl/materialx/stdlib_1_6.mdl
index 601a10fda2..f5d661b17e 100644
--- a/source/MaterialXGenMdl/mdl/materialx/stdlib_1_6.mdl
+++ b/source/MaterialXGenMdl/mdl/materialx/stdlib_1_6.mdl
@@ -88,6 +88,24 @@ export material mx_surface_unlit(
     }
 }
 
+// Helper function provides texture lookup coordinate with `closest` lookup type support
+float2 tex_lookup_coord(float2 st, int tex_width, int tex_height, core::mx_filterlookup_type lookup_type, bool flip_v)
+{
+    float2 coord = st;
+
+    // `closest` lookup
+    if (lookup_type == core::mx_filterlookup_type_closest)
+    {
+        int2 tex_size(tex_width, tex_height);
+        coord = (math::floor(coord * tex_size) + float2(0.5)) / tex_size;
+    }
+
+    // `linear` and `cubic` uses the original coord
+    coord = flip_v ? float2(coord.x, 1.0 - coord.y) : coord;
+
+    return coord;
+}
+
 // NOTE: need to map MaterialX return type overloads to different function names
 //       or we require the mx_default to be always set explicitly
 
@@ -121,8 +139,7 @@ export float mx_image_float(
 	uniform core::mx_filterlookup_type mxp_filtertype = core::mx_filterlookup_type(core::mx_filterlookup_type_linear)	
 	[[
 		anno::description("Enumeration {closest,linear,cubic}."),
-		anno::display_name("Filter Type"),
-        anno::unused()
+		anno::display_name("Filter Type")
 	]],
 	uniform string mxp_framerange = string("")	
 	[[
@@ -160,9 +177,12 @@ export float mx_image_float(
 		return mxp_default;
 
 	float returnValue = ::tex::lookup_float(tex: mxp_file, 
-						coord: mxp_flip_v
-							? float2(mxp_texcoord.x, 1.0f - mxp_texcoord.y) 
-							: mxp_texcoord,
+						coord: tex_lookup_coord(
+							mxp_texcoord,
+							tex::width(mxp_file),
+							tex::height(mxp_file),
+							mxp_filtertype,
+							mxp_flip_v),
 						wrap_u: map_addressmode(mxp_uaddressmode),
 						wrap_v: map_addressmode(mxp_vaddressmode));
 	return returnValue;
@@ -198,8 +218,7 @@ export color mx_image_color3(
 	uniform core::mx_filterlookup_type mxp_filtertype = core::mx_filterlookup_type(core::mx_filterlookup_type_linear)	
 	[[
 		anno::description("Enumeration {closest,linear,cubic}."),
-		anno::display_name("Filter Type"),
-        anno::unused()
+		anno::display_name("Filter Type")
 	]],
 	uniform string mxp_framerange = string("")	
 	[[
@@ -237,9 +256,12 @@ export color mx_image_color3(
 		return mxp_default;
 
 	color returnValue = ::tex::lookup_color(tex: mxp_file, 
-						coord: mxp_flip_v
-							? float2(mxp_texcoord.x, 1.0f - mxp_texcoord.y) 
-							: mxp_texcoord,
+						coord: tex_lookup_coord(
+							mxp_texcoord,
+							tex::width(mxp_file),
+							tex::height(mxp_file),
+							mxp_filtertype,
+							mxp_flip_v),
 						wrap_u: map_addressmode(mxp_uaddressmode),
 						wrap_v: map_addressmode(mxp_vaddressmode));
 	return returnValue;
@@ -275,8 +297,7 @@ export core::color4 mx_image_color4(
 	uniform core::mx_filterlookup_type mxp_filtertype = core::mx_filterlookup_type(core::mx_filterlookup_type_linear)	
 	[[
 		anno::description("Enumeration {closest,linear,cubic}."),
-		anno::display_name("Filter Type"),
-        anno::unused()
+		anno::display_name("Filter Type")
 	]],
 	uniform string mxp_framerange = string("")	
 	[[
@@ -314,9 +335,12 @@ export core::color4 mx_image_color4(
 		return mxp_default;
 
 	core::color4 returnValue = core::mk_color4(::tex::lookup_float4(tex: mxp_file, 
-						coord: mxp_flip_v
-							? float2(mxp_texcoord.x, 1.0f - mxp_texcoord.y) 
-							: mxp_texcoord,
+						coord: tex_lookup_coord(
+							mxp_texcoord,
+							tex::width(mxp_file),
+							tex::height(mxp_file),
+							mxp_filtertype,
+							mxp_flip_v),
 						wrap_u: map_addressmode(mxp_uaddressmode),
 						wrap_v: map_addressmode(mxp_vaddressmode)));
 	return returnValue;
@@ -352,8 +376,7 @@ export float2 mx_image_vector2(
 	uniform core::mx_filterlookup_type mxp_filtertype = core::mx_filterlookup_type(core::mx_filterlookup_type_linear)	
 	[[
 		anno::description("Enumeration {closest,linear,cubic}."),
-		anno::display_name("Filter Type"),
-        anno::unused()
+		anno::display_name("Filter Type")
 	]],
 	uniform string mxp_framerange = string("")	
 	[[
@@ -391,9 +414,12 @@ export float2 mx_image_vector2(
 		return mxp_default;
 
 	float2 returnValue = ::tex::lookup_float2(tex: mxp_file, 
-						coord: mxp_flip_v
-							? float2(mxp_texcoord.x, 1.0f - mxp_texcoord.y) 
-							: mxp_texcoord,
+						coord: tex_lookup_coord(
+							mxp_texcoord,
+							tex::width(mxp_file),
+							tex::height(mxp_file),
+							mxp_filtertype,
+							mxp_flip_v),
 						wrap_u: map_addressmode(mxp_uaddressmode),
 						wrap_v: map_addressmode(mxp_vaddressmode));
 	return returnValue;
@@ -429,8 +455,7 @@ export float3 mx_image_vector3(
 	uniform core::mx_filterlookup_type mxp_filtertype = core::mx_filterlookup_type(core::mx_filterlookup_type_linear)	
 	[[
 		anno::description("Enumeration {closest,linear,cubic}."),
-		anno::display_name("Filter Type"),
-        anno::unused()
+		anno::display_name("Filter Type")
 	]],
 	uniform string mxp_framerange = string("")	
 	[[
@@ -468,9 +493,12 @@ export float3 mx_image_vector3(
 		return mxp_default;
 
 	float3 returnValue = ::tex::lookup_float3(tex: mxp_file, 
-						coord: mxp_flip_v
-							? float2(mxp_texcoord.x, 1.0f - mxp_texcoord.y) 
-							: mxp_texcoord,
+						coord: tex_lookup_coord(
+							mxp_texcoord,
+							tex::width(mxp_file),
+							tex::height(mxp_file),
+							mxp_filtertype,
+							mxp_flip_v),
 						wrap_u: map_addressmode(mxp_uaddressmode),
 						wrap_v: map_addressmode(mxp_vaddressmode));
 	return returnValue;
@@ -506,8 +534,7 @@ export float4 mx_image_vector4(
 	uniform core::mx_filterlookup_type mxp_filtertype = core::mx_filterlookup_type(core::mx_filterlookup_type_linear)	
 	[[
 		anno::description("Enumeration {closest,linear,cubic}."),
-		anno::display_name("Filter Type"),
-        anno::unused()
+		anno::display_name("Filter Type")
 	]],
 	uniform string mxp_framerange = string("")	
 	[[
@@ -545,9 +572,12 @@ export float4 mx_image_vector4(
 		return mxp_default;
 
 	float4 returnValue = ::tex::lookup_float4(tex: mxp_file, 
-						coord: mxp_flip_v
-							? float2(mxp_texcoord.x, 1.0f - mxp_texcoord.y) 
-							: mxp_texcoord,
+						coord: tex_lookup_coord(
+							mxp_texcoord,
+							tex::width(mxp_file),
+							tex::height(mxp_file),
+							mxp_filtertype,
+							mxp_flip_v),
 						wrap_u: map_addressmode(mxp_uaddressmode),
 						wrap_v: map_addressmode(mxp_vaddressmode));
 	return returnValue;