diff --git a/src/hb-aat-layout-common.hh b/src/hb-aat-layout-common.hh
index 8e7b7b529..e70ce9717 100644
--- a/src/hb-aat-layout-common.hh
+++ b/src/hb-aat-layout-common.hh
@@ -30,6 +30,9 @@
 #include "hb-aat-layout.hh"
 #include "hb-open-type.hh"
 
+namespace OT {
+struct GDEF;
+};
 
 namespace AAT {
 
@@ -863,6 +866,7 @@ struct hb_aat_apply_context_t :
   hb_buffer_t *buffer;
   hb_sanitize_context_t sanitizer;
   const ankr *ankr_table;
+  const OT::GDEF *gdef_table;
 
   /* Unused. For debug tracing only. */
   unsigned int lookup_index;
diff --git a/src/hb-aat-layout-morx-table.hh b/src/hb-aat-layout-morx-table.hh
index dea69c9ab..a807bdcfc 100644
--- a/src/hb-aat-layout-morx-table.hh
+++ b/src/hb-aat-layout-morx-table.hh
@@ -30,6 +30,7 @@
 #include "hb-open-type.hh"
 #include "hb-aat-layout-common.hh"
 #include "hb-ot-layout-common.hh"
+#include "hb-ot-layout-gdef-table.hh"
 #include "hb-aat-map.hh"
 
 /*
@@ -215,7 +216,9 @@ struct ContextualSubtable
 			     hb_aat_apply_context_t *c_) :
 	ret (false),
 	c (c_),
+	gdef (*c->gdef_table),
 	mark_set (false),
+	has_glyph_classes (gdef.has_glyph_classes ()),
 	mark (0),
 	table (table_),
 	subs (table+table->substitutionTables) {}
@@ -263,6 +266,9 @@ struct ContextualSubtable
       {
 	buffer->unsafe_to_break (mark, hb_min (buffer->idx + 1, buffer->len));
 	buffer->info[mark].codepoint = *replacement;
+	if (has_glyph_classes)
+	  _hb_glyph_info_set_glyph_props (&buffer->info[mark],
+					  gdef.get_glyph_props (*replacement));
 	ret = true;
       }
 
@@ -287,6 +293,9 @@ struct ContextualSubtable
       if (replacement)
       {
 	buffer->info[idx].codepoint = *replacement;
+	if (has_glyph_classes)
+	  _hb_glyph_info_set_glyph_props (&buffer->info[idx],
+					  gdef.get_glyph_props (*replacement));
 	ret = true;
       }
 
@@ -301,7 +310,9 @@ struct ContextualSubtable
     bool ret;
     private:
     hb_aat_apply_context_t *c;
+    const OT::GDEF &gdef;
     bool mark_set;
+    bool has_glyph_classes;
     unsigned int mark;
     const ContextualSubtable *table;
     const UnsizedListOfOffset16To<Lookup<HBGlyphID>, HBUINT, false> &subs;
@@ -599,6 +610,9 @@ struct NoncontextualSubtable
   {
     TRACE_APPLY (this);
 
+    const OT::GDEF &gdef (*c->gdef_table);
+    bool has_glyph_classes = gdef.has_glyph_classes ();
+
     bool ret = false;
     unsigned int num_glyphs = c->face->get_num_glyphs ();
 
@@ -610,6 +624,9 @@ struct NoncontextualSubtable
       if (replacement)
       {
 	info[i].codepoint = *replacement;
+	if (has_glyph_classes)
+	  _hb_glyph_info_set_glyph_props (&info[i],
+					  gdef.get_glyph_props (*replacement));
 	ret = true;
       }
     }
diff --git a/src/hb-aat-layout.cc b/src/hb-aat-layout.cc
index 0e9f2b495..63f602855 100644
--- a/src/hb-aat-layout.cc
+++ b/src/hb-aat-layout.cc
@@ -55,6 +55,7 @@ AAT::hb_aat_apply_context_t::hb_aat_apply_context_t (const hb_ot_shape_plan_t *p
 						       buffer (buffer_),
 						       sanitizer (),
 						       ankr_table (&Null (AAT::ankr)),
+						       gdef_table (face->table.GDEF->table),
 						       lookup_index (0)
 {
   sanitizer.init (blob);
@@ -79,7 +80,7 @@ AAT::hb_aat_apply_context_t::set_ankr_table (const AAT::ankr *ankr_table_)
  * @short_description: Apple Advanced Typography Layout
  * @include: hb-aat.h
  *
- * Functions for querying AAT Layout features in the font face. 
+ * Functions for querying AAT Layout features in the font face.
  *
  * HarfBuzz supports all of the AAT tables used to implement shaping. Other
  * AAT tables and their associated features are not supported.
@@ -172,13 +173,13 @@ static const hb_aat_feature_mapping_t feature_mappings[] =
   {HB_TAG ('z','e','r','o'), HB_AAT_LAYOUT_FEATURE_TYPE_TYPOGRAPHIC_EXTRAS,      HB_AAT_LAYOUT_FEATURE_SELECTOR_SLASHED_ZERO_ON,                HB_AAT_LAYOUT_FEATURE_SELECTOR_SLASHED_ZERO_OFF},
 };
 
-/** 
+/**
  * hb_aat_layout_find_feature_mapping:
  * @tag: The requested #hb_tag_t feature tag
  *
  * Fetches the AAT feature-and-selector combination that corresponds
  * to a given OpenType feature tag.
- *  
+ *
  * Return value: the AAT features and selectors corresponding to the
  * OpenType feature tag queried
  *