diff --git a/src/Makefile.am b/src/Makefile.am
index 13107b9..b68d14b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -52,6 +52,7 @@ HBSOURCES += \
 	hb-ot-shape.cc \
 	hb-ot-shape-complex-arabic.cc \
 	hb-ot-shape-complex-arabic-table.h \
+	hb-ot-shape-complex-mongolian.cc \
 	hb-ot-shape-complex-private.hh \
 	hb-ot-shape-private.hh \
 	hb-ot-tag.c \
diff --git a/src/hb-ot-shape-complex-mongolian.cc b/src/hb-ot-shape-complex-mongolian.cc
new file mode 100644
index 0000000..5406917
--- /dev/null
+++ b/src/hb-ot-shape-complex-mongolian.cc
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2010  Google, Inc.
+ *
+ *  This is part of HarfBuzz, a text shaping library.
+ *
+ * Permission is hereby granted, without written agreement and without
+ * license or royalty fees, to use, copy, modify, and distribute this
+ * software and its documentation for any purpose, provided that the
+ * above copyright notice and the following two paragraphs appear in
+ * all copies of this software.
+ *
+ * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
+ * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
+ * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
+ * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
+ * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
+ * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
+ *
+ * Author(s): Erdene-Ochir Tuguldur <tugstugi@yahoo.com>
+ */
+
+#include "hb-ot-shape-complex-private.hh"
+
+HB_BEGIN_DECLS
+
+
+/* buffer var allocations */
+#define mongolian_shaping_action() var2.u32 /* mongolian shaping action */
+
+
+/*
+ * Bits used in the joining tables
+ */
+enum {
+  JOINING_TYPE_U			= 0, // non joining
+  /* We don't have JOINING_TYPE_L and JOINING_TYPE_R since mongolian letters are dual joining. */
+  JOINING_TYPE_D			= 1,
+  JOINING_TYPE_C			= JOINING_TYPE_D,
+  NUM_STATE_MACHINE_COLS	= 2,
+  JOINING_TYPE_T 			= 3
+};
+
+/*
+ * Joining types:
+ */
+
+static unsigned int get_joining_type (hb_codepoint_t u, hb_category_t gen_cat)
+{
+  if (likely (0x1800 <= u && u <= 0x18AA)) {
+    if (likely (u == 0x1807 || u == 0x180A)) {
+      /* sibe syllable boundary marker and mongolian niragu */
+      return JOINING_TYPE_D;
+    }
+    if (likely (0x180B <= u && u <= 0x180D)) {
+      /* mongolian free variation selectors */
+      return JOINING_TYPE_T;
+    }
+    if (likely (0x1820 <= u && u <= 0x1877)) {
+      /* letters */
+      return JOINING_TYPE_D;
+    }
+    if (likely (0x1880 <= u && u <= 0x18AA)) {
+      /* Ali Gali letters */
+      return JOINING_TYPE_D;
+    }
+    return JOINING_TYPE_U;
+  }
+
+  if (unlikely ((u & ~(0x200C^0x200D)) == 0x200C)) {
+    return u == 0x200C ? JOINING_TYPE_U : JOINING_TYPE_C;
+  }
+
+  return ((1<<gen_cat) & ((1<<HB_CATEGORY_NON_SPACING_MARK)|(1<<HB_CATEGORY_ENCLOSING_MARK)|(1<<HB_CATEGORY_FORMAT))) ?
+	 JOINING_TYPE_T : JOINING_TYPE_U;
+}
+
+
+
+static const hb_tag_t mongolian_features[] =
+{
+  HB_TAG('i','n','i','t'),
+  HB_TAG('m','e','d','i'),
+  HB_TAG('f','i','n','a'),
+  HB_TAG('i','s','o','l'),
+  HB_TAG_NONE
+};
+
+
+/* Same order as the feature array */
+enum {
+  INIT,
+  MEDI,
+  FINA,
+  ISOL,
+  NONE,
+  NUM_FEATURES = 4,
+  TOTAL_NUM_FEATURES = NONE
+};
+
+static const struct mongolian_state_table_entry {
+	uint8_t prev_action;
+	uint8_t curr_action;
+	uint8_t next_state;
+	uint8_t padding;
+} mongolian_state_table[][NUM_STATE_MACHINE_COLS] =
+{
+  /*   jt_U,          jt_D */
+
+  /* State 0: prev was U, not willing to join. */
+  { {NONE,NONE,0}, {NONE,ISOL,1},},
+
+  /* State 1: prev was D/ISOL, willing to join. */
+  { {NONE,NONE,0}, {INIT,FINA,2}, },
+
+  /* State 2: prev was D/FINA, willing to join. */
+  { {NONE,NONE,0}, {MEDI,FINA,2}, }
+};
+
+
+
+void
+_hb_ot_shape_complex_collect_features_mongolian	(hb_ot_shape_plan_t *plan, const hb_segment_properties_t  *props)
+{
+  for (unsigned int i = 0; i < NUM_FEATURES; i++)
+    plan->map.add_bool_feature (mongolian_features[i], false);
+}
+
+void
+_hb_ot_shape_complex_setup_masks_mongolian	(hb_ot_shape_context_t *c)
+{
+  unsigned int count = c->buffer->len;
+  unsigned int prev = 0, state = 0;
+
+  for (unsigned int i = 0; i < count; i++)
+  {
+    unsigned int this_type = get_joining_type (c->buffer->info[i].codepoint, (hb_category_t) c->buffer->info[i].general_category());
+
+    if (unlikely (this_type == JOINING_TYPE_T)) {
+      c->buffer->info[i].mongolian_shaping_action() = NONE;
+      continue;
+    }
+
+    const mongolian_state_table_entry *entry = &mongolian_state_table[state][this_type];
+
+    if (entry->prev_action != NONE)
+      c->buffer->info[prev].mongolian_shaping_action() = entry->prev_action;
+
+    c->buffer->info[i].mongolian_shaping_action() = entry->curr_action;
+
+    prev = i;
+    state = entry->next_state;
+  }
+
+  hb_mask_t mask_array[TOTAL_NUM_FEATURES + 1] = {0};
+  for (unsigned int i = 0; i < NUM_FEATURES; i++)
+    mask_array[i] = c->plan->map.get_1_mask (mongolian_features[i]);
+
+  for (unsigned int i = 0; i < count; i++)
+    c->buffer->info[i].mask |= mask_array[c->buffer->info[i].mongolian_shaping_action()];
+}
+
+
+HB_END_DECLS
diff --git a/src/hb-ot-shape-complex-private.hh b/src/hb-ot-shape-complex-private.hh
index a3796b4..55d0fd6 100644
--- a/src/hb-ot-shape-complex-private.hh
+++ b/src/hb-ot-shape-complex-private.hh
@@ -42,6 +42,8 @@ hb_ot_shape_complex_categorize (const hb_segment_properties_t *props)
     case HB_SCRIPT_NKO:
     case HB_SCRIPT_SYRIAC:
       return hb_ot_complex_shaper_arabic;
+    case HB_SCRIPT_MONGOLIAN:
+      return hb_ot_complex_shaper_mongolian;
 
     default:
       return hb_ot_complex_shaper_none;
@@ -58,7 +60,8 @@ hb_ot_shape_complex_categorize (const hb_segment_properties_t *props)
  * Shapers should use plan->map to add their features.
  */
 
-HB_INTERNAL void _hb_ot_shape_complex_collect_features_arabic	(hb_ot_shape_plan_t *plan, const hb_segment_properties_t  *props);
+HB_INTERNAL void _hb_ot_shape_complex_collect_features_arabic		(hb_ot_shape_plan_t *plan, const hb_segment_properties_t  *props);
+HB_INTERNAL void _hb_ot_shape_complex_collect_features_mongolian	(hb_ot_shape_plan_t *plan, const hb_segment_properties_t  *props);
 
 static inline void
 hb_ot_shape_complex_collect_features (hb_ot_shape_plan_t *plan,
@@ -66,6 +69,7 @@ hb_ot_shape_complex_collect_features (hb_ot_shape_plan_t *plan,
 {
   switch (plan->shaper) {
     case hb_ot_complex_shaper_arabic:	_hb_ot_shape_complex_collect_features_arabic (plan, props);	return;
+    case hb_ot_complex_shaper_mongolian: _hb_ot_shape_complex_collect_features_mongolian (plan, props);	return;
     case hb_ot_complex_shaper_none:	default:							return;
   }
 }
@@ -79,12 +83,14 @@ hb_ot_shape_complex_collect_features (hb_ot_shape_plan_t *plan,
  */
 
 HB_INTERNAL void _hb_ot_shape_complex_setup_masks_arabic	(hb_ot_shape_context_t *c);
+HB_INTERNAL void _hb_ot_shape_complex_setup_masks_mongolian	(hb_ot_shape_context_t *c);
 
 static inline void
 hb_ot_shape_complex_setup_masks (hb_ot_shape_context_t *c)
 {
   switch (c->plan->shaper) {
-    case hb_ot_complex_shaper_arabic:	_hb_ot_shape_complex_setup_masks_arabic (c);	return;
+    case hb_ot_complex_shaper_arabic:		_hb_ot_shape_complex_setup_masks_arabic (c);	return;
+    case hb_ot_complex_shaper_mongolian:	_hb_ot_shape_complex_setup_masks_mongolian (c);	return;
     case hb_ot_complex_shaper_none:	default:					return;
   }
 }
diff --git a/src/hb-ot-shape-private.hh b/src/hb-ot-shape-private.hh
index deaec97..20370b9 100644
--- a/src/hb-ot-shape-private.hh
+++ b/src/hb-ot-shape-private.hh
@@ -43,7 +43,8 @@ HB_BEGIN_DECLS
 
 enum hb_ot_complex_shaper_t {
   hb_ot_complex_shaper_none,
-  hb_ot_complex_shaper_arabic
+  hb_ot_complex_shaper_arabic,
+  hb_ot_complex_shaper_mongolian
 };