diff --git a/libraries/pbrlib/genglsl/mx_backfacing_boolean.inline b/libraries/pbrlib/genglsl/mx_backfacing_boolean.inline
deleted file mode 100644
index 5f93b07e24..0000000000
--- a/libraries/pbrlib/genglsl/mx_backfacing_boolean.inline
+++ /dev/null
@@ -1 +0,0 @@
-(!gl_FrontFacing)
diff --git a/libraries/pbrlib/genglsl/mx_backfacing_float.inline b/libraries/pbrlib/genglsl/mx_backfacing_float.inline
deleted file mode 100644
index 0b518ff8f5..0000000000
--- a/libraries/pbrlib/genglsl/mx_backfacing_float.inline
+++ /dev/null
@@ -1 +0,0 @@
-float(!gl_FrontFacing)
diff --git a/libraries/pbrlib/genglsl/mx_backfacing_integer.inline b/libraries/pbrlib/genglsl/mx_backfacing_integer.inline
deleted file mode 100644
index 1e76004c74..0000000000
--- a/libraries/pbrlib/genglsl/mx_backfacing_integer.inline
+++ /dev/null
@@ -1 +0,0 @@
-int(!gl_FrontFacing)
diff --git a/libraries/pbrlib/genglsl/pbrlib_genglsl_impl.mtlx b/libraries/pbrlib/genglsl/pbrlib_genglsl_impl.mtlx
index a77dcf131c..0e708d1d3f 100644
--- a/libraries/pbrlib/genglsl/pbrlib_genglsl_impl.mtlx
+++ b/libraries/pbrlib/genglsl/pbrlib_genglsl_impl.mtlx
@@ -54,11 +54,6 @@
   <!-- <light> -->
   <implementation name="IM_light_genglsl" nodedef="ND_light" target="genglsl"/>
 
-  <!-- <backfacing> -->
-  <implementation name="IM_backfacing_boolean_genglsl" nodedef="ND_backfacing_boolean" file="pbrlib/genglsl/mx_backfacing_boolean.inline" target="genglsl"/>
-  <implementation name="IM_backfacing_integer_genglsl" nodedef="ND_backfacing_integer" file="pbrlib/genglsl/mx_backfacing_integer.inline" target="genglsl"/>
-  <implementation name="IM_backfacing_float_genglsl" nodedef="ND_backfacing_float" file="pbrlib/genglsl/mx_backfacing_float.inline" target="genglsl"/>
-
   <!-- <roughness_anisotropy> -->
   <implementation name="IM_roughness_anisotropy_genglsl" nodedef="ND_roughness_anisotropy" file="pbrlib/genglsl/mx_roughness_anisotropy.glsl" function="mx_roughness_anisotropy" target="genglsl"/>
 
diff --git a/libraries/pbrlib/genmdl/pbrlib_genmdl_impl.mtlx b/libraries/pbrlib/genmdl/pbrlib_genmdl_impl.mtlx
index 639423cf4b..4480721251 100644
--- a/libraries/pbrlib/genmdl/pbrlib_genmdl_impl.mtlx
+++ b/libraries/pbrlib/genmdl/pbrlib_genmdl_impl.mtlx
@@ -77,11 +77,6 @@
   <implementation name="IM_multiply_edfC_genmdl" nodedef="ND_multiply_edfC" sourcecode="{{in1}}" target="genmdl"/> <!-- TODO: Implement properly -->
   <implementation name="IM_multiply_edfF_genmdl" nodedef="ND_multiply_edfF" sourcecode="{{in1}}" target="genmdl"/> <!-- TODO: Implement properly -->
 
-  <!-- <backfacing> -->
-  <implementation name="IM_backfacing_boolean_genmdl" nodedef="ND_backfacing_boolean" sourcecode="mx::pbrlib::mx_backfacing_bool()" target="genmdl"/>
-  <implementation name="IM_backfacing_integer_genmdl" nodedef="ND_backfacing_integer" sourcecode="mx::pbrlib::mx_backfacing_int()" target="genmdl"/>
-  <implementation name="IM_backfacing_float_genmdl" nodedef="ND_backfacing_float" sourcecode="mx::pbrlib::mx_backfacing_float()" target="genmdl"/>
-
   <!-- <roughness_anisotropy> -->
   <implementation name="IM_roughness_anisotropy_genmdl" nodedef="ND_roughness_anisotropy" sourcecode="mx::pbrlib::mx_roughness_anisotropy(mxp_roughness:{{roughness}}, mxp_anisotropy:{{anisotropy}})" target="genmdl"/>
 
diff --git a/libraries/pbrlib/genosl/mx_backfacing_boolean.inline b/libraries/pbrlib/genosl/mx_backfacing_boolean.inline
deleted file mode 100644
index 4a21396910..0000000000
--- a/libraries/pbrlib/genosl/mx_backfacing_boolean.inline
+++ /dev/null
@@ -1 +0,0 @@
-backfacing()
diff --git a/libraries/pbrlib/genosl/mx_backfacing_float.inline b/libraries/pbrlib/genosl/mx_backfacing_float.inline
deleted file mode 100644
index f0d9f762b7..0000000000
--- a/libraries/pbrlib/genosl/mx_backfacing_float.inline
+++ /dev/null
@@ -1 +0,0 @@
-float(backfacing())
diff --git a/libraries/pbrlib/genosl/mx_backfacing_integer.inline b/libraries/pbrlib/genosl/mx_backfacing_integer.inline
deleted file mode 100644
index 4a21396910..0000000000
--- a/libraries/pbrlib/genosl/mx_backfacing_integer.inline
+++ /dev/null
@@ -1 +0,0 @@
-backfacing()
diff --git a/libraries/pbrlib/genosl/pbrlib_genosl_impl.mtlx b/libraries/pbrlib/genosl/pbrlib_genosl_impl.mtlx
index 3ef621f371..663737bb16 100644
--- a/libraries/pbrlib/genosl/pbrlib_genosl_impl.mtlx
+++ b/libraries/pbrlib/genosl/pbrlib_genosl_impl.mtlx
@@ -55,11 +55,6 @@
   <implementation name="IM_displacement_float_genosl" nodedef="ND_displacement_float" file="pbrlib/genosl/mx_displacement_float.osl" function="mx_displacement_float" target="genosl"/>
   <implementation name="IM_displacement_vector3_genosl" nodedef="ND_displacement_vector3" file="pbrlib/genosl/mx_displacement_vector3.osl" function="mx_displacement_vector3" target="genosl"/>
 
-  <!-- <backfacing> -->
-  <implementation name="IM_backfacing_boolean_genosl" nodedef="ND_backfacing_boolean" file="pbrlib/genosl/mx_backfacing_boolean.inline" target="genosl"/>
-  <implementation name="IM_backfacing_integer_genosl" nodedef="ND_backfacing_integer" file="pbrlib/genosl/mx_backfacing_integer.inline" target="genosl"/>
-  <implementation name="IM_backfacing_float_genosl" nodedef="ND_backfacing_float" file="pbrlib/genosl/mx_backfacing_float.inline" target="genosl"/>
-
   <!-- <roughness_anisotropy> -->
   <implementation name="IM_roughness_anisotropy_genosl" nodedef="ND_roughness_anisotropy" file="pbrlib/genosl/mx_roughness_anisotropy.osl" function="mx_roughness_anisotropy" target="genosl"/>
 
diff --git a/libraries/pbrlib/pbrlib_defs.mtlx b/libraries/pbrlib/pbrlib_defs.mtlx
index 65b14dc8ef..7f8719230f 100644
--- a/libraries/pbrlib/pbrlib_defs.mtlx
+++ b/libraries/pbrlib/pbrlib_defs.mtlx
@@ -384,19 +384,6 @@
     <output name="out" type="VDF"/>
   </nodedef>
 
-  <!--
-    Node: <backfacing>
-  -->
-  <nodedef name="ND_backfacing_boolean" node="backfacing" nodegroup="pbr">
-    <output name="out" type="boolean"/>
-  </nodedef>
-  <nodedef name="ND_backfacing_integer" node="backfacing" nodegroup="pbr">
-    <output name="out" type="integer"/>
-  </nodedef>
-  <nodedef name="ND_backfacing_float" node="backfacing" nodegroup="pbr">
-    <output name="out" type="float"/>
-  </nodedef>
-
   <!--
     Node: <roughness_anisotropy>
     Calculates anisotropic surface roughness from a scalar roughness and anisotropy parameterization.
diff --git a/source/MaterialXGenMdl/mdl/materialx/pbrlib.mdl b/source/MaterialXGenMdl/mdl/materialx/pbrlib.mdl
index f99d146ace..c1e548e9d6 100644
--- a/source/MaterialXGenMdl/mdl/materialx/pbrlib.mdl
+++ b/source/MaterialXGenMdl/mdl/materialx/pbrlib.mdl
@@ -787,13 +787,6 @@ export material mx_multiply_vdf_float(
     )
 );
 
-
-// NOTE: mx_backfacing, not supported in MDL, and requires function overlaod
-//       based on the return type. We return always false.
-export bool  mx_backfacing_bool()  { return false; }
-export int   mx_backfacing_int()   { return 0; }
-export float mx_backfacing_float() { return 0.0; }
-
 export float2 mx_roughness_anisotropy(
     float mxp_roughness = 0.0,
     float mxp_anisotropy = 0.0