diff --git a/examples/mxnet/tree_lstm/README.md b/examples/mxnet/tree_lstm/README.md
new file mode 100644
index 000000000000..49dfb9e2643b
--- /dev/null
+++ b/examples/mxnet/tree_lstm/README.md
@@ -0,0 +1,19 @@
+# Tree-LSTM
+This is a re-implementation of the following paper:
+
+> [**Improved Semantic Representations From Tree-Structured Long Short-Term Memory Networks**](http://arxiv.org/abs/1503.00075)
+> *Kai Sheng Tai, Richard Socher, and Christopher Manning*.
+
+The provided implementation can achieve a test accuracy of 51.72 which is comparable with the result reported in the original paper: 51.0(±0.5).
+
+## Data
+The script will download the [SST dataset] (http://nlp.stanford.edu/sentiment/index.html) and the GloVe 840B.300d embedding automatically if `--use-glove` is specified (note: download may take a while).
+
+## Usage
+```
+python train.py --gpu 0
+```
+
+## Speed Test
+
+See https://docs.google.com/spreadsheets/d/1eCQrVn7g0uWriz63EbEDdes2ksMdKdlbWMyT8PSU4rc .
diff --git a/examples/mxnet/tree_lstm/train.py b/examples/mxnet/tree_lstm/train.py
new file mode 100644
index 000000000000..02ca1322b391
--- /dev/null
+++ b/examples/mxnet/tree_lstm/train.py
@@ -0,0 +1,208 @@
+import argparse
+import time
+import warnings
+import zipfile
+import os
+
+os.environ['DGLBACKEND'] = 'mxnet'
+os.environ['MXNET_GPU_MEM_POOL_TYPE'] = 'Round'
+
+import numpy as np
+import mxnet as mx
+from mxnet import gluon
+
+import dgl
+import dgl.data as data
+
+from tree_lstm import TreeLSTM
+
+def batcher(ctx):
+    def batcher_dev(batch):
+        batch_trees = dgl.batch(batch)
+        return data.SSTBatch(graph=batch_trees,
+                             mask=batch_trees.ndata['mask'].as_in_context(ctx),
+                             wordid=batch_trees.ndata['x'].as_in_context(ctx),
+                             label=batch_trees.ndata['y'].as_in_context(ctx))
+    return batcher_dev
+
+def prepare_glove():
+    if not (os.path.exists('glove.840B.300d.txt')
+            and data.utils.check_sha1('glove.840B.300d.txt',
+                                      sha1_hash='294b9f37fa64cce31f9ebb409c266fc379527708')):
+        zip_path = data.utils.download('http://nlp.stanford.edu/data/glove.840B.300d.zip',
+                                       sha1_hash='8084fbacc2dee3b1fd1ca4cc534cbfff3519ed0d')
+        with zipfile.ZipFile(zip_path, 'r') as zf:
+            zf.extractall()
+        if not data.utils.check_sha1('glove.840B.300d.txt',
+                                     sha1_hash='294b9f37fa64cce31f9ebb409c266fc379527708'):
+            warnings.warn('The downloaded glove embedding file checksum mismatch. File content '
+                          'may be corrupted.')
+
+def main(args):
+    np.random.seed(args.seed)
+    mx.random.seed(args.seed)
+
+    best_epoch = -1
+    best_dev_acc = 0
+
+    cuda = args.gpu >= 0
+    if cuda:
+        if args.gpu in mx.test_utils.list_gpus():
+            ctx = mx.gpu(args.gpu)
+        else:
+            print('Requested GPU id {} was not found. Defaulting to CPU implementation'.format(args.gpu))
+            ctx = mx.cpu()
+
+    if args.use_glove:
+        prepare_glove()
+
+    trainset = data.SST()
+    train_loader = gluon.data.DataLoader(dataset=trainset,
+                                         batch_size=args.batch_size,
+                                         batchify_fn=batcher(ctx),
+                                         shuffle=True,
+                                         num_workers=0)
+    devset = data.SST(mode='dev')
+    dev_loader = gluon.data.DataLoader(dataset=devset,
+                                       batch_size=100,
+                                       batchify_fn=batcher(ctx),
+                                       shuffle=True,
+                                       num_workers=0)
+
+    testset = data.SST(mode='test')
+    test_loader = gluon.data.DataLoader(dataset=testset,
+                                        batch_size=100,
+                                        batchify_fn=batcher(ctx),
+                                        shuffle=False, num_workers=0)
+
+    model = TreeLSTM(trainset.num_vocabs,
+                     args.x_size,
+                     args.h_size,
+                     trainset.num_classes,
+                     args.dropout,
+                     cell_type='childsum' if args.child_sum else 'nary',
+                     pretrained_emb = trainset.pretrained_emb,
+                     ctx=ctx)
+    print(model)
+    params_ex_emb =[x for x in model.collect_params().values()
+                    if x.grad_req != 'null' and x.shape[0] != trainset.num_vocabs]
+    params_emb = list(model.embedding.collect_params().values())
+    for p in params_emb:
+        p.lr_mult = 0.1
+
+    model.initialize(mx.init.Xavier(magnitude=1), ctx=ctx)
+    model.hybridize()
+    trainer = gluon.Trainer(model.collect_params('^(?!embedding).*$'), 'adagrad',
+                            {'learning_rate': args.lr, 'wd': args.weight_decay})
+    trainer_emb = gluon.Trainer(model.collect_params('^embedding.*$'), 'adagrad',
+                                {'learning_rate': args.lr})
+
+    dur = []
+    L = gluon.loss.SoftmaxCrossEntropyLoss(axis=1)
+    for epoch in range(args.epochs):
+        t_epoch = time.time()
+        for step, batch in enumerate(train_loader):
+            g = batch.graph
+            n = g.number_of_nodes()
+
+            # TODO begin_states function?
+            h = mx.nd.zeros((n, args.h_size), ctx=ctx)
+            c = mx.nd.zeros((n, args.h_size), ctx=ctx)
+            if step >= 3:
+                t0 = time.time() # tik
+            with mx.autograd.record():
+                pred = model(batch, h, c)
+                loss = L(pred, batch.label)
+
+            loss.backward()
+            trainer.step(args.batch_size)
+            trainer_emb.step(args.batch_size)
+
+            if step >= 3:
+                dur.append(time.time() - t0) # tok
+
+            if step > 0 and step % args.log_every == 0:
+                pred = pred.argmax(axis=1)
+                acc = (batch.label == pred).sum()
+                root_ids = [i for i in range(batch.graph.number_of_nodes()) if batch.graph.out_degree(i)==0]
+                root_acc = np.sum(batch.label.asnumpy()[root_ids] == pred.asnumpy()[root_ids])
+
+                print("Epoch {:05d} | Step {:05d} | Loss {:.4f} | Acc {:.4f} | Root Acc {:.4f} | Time(s) {:.4f}".format(
+                    epoch, step, loss.sum().asscalar(), 1.0*acc.asscalar()/len(batch.label), 1.0*root_acc/len(root_ids), np.mean(dur)))
+        print('Epoch {:05d} training time {:.4f}s'.format(epoch, time.time() - t_epoch))
+
+        # eval on dev set
+        accs = []
+        root_accs = []
+        for step, batch in enumerate(dev_loader):
+            g = batch.graph
+            n = g.number_of_nodes()
+            h = mx.nd.zeros((n, args.h_size), ctx=ctx)
+            c = mx.nd.zeros((n, args.h_size), ctx=ctx)
+            pred = model(batch, h, c).argmax(1)
+
+            acc = (batch.label == pred).sum().asscalar()
+            accs.append([acc, len(batch.label)])
+            root_ids = [i for i in range(batch.graph.number_of_nodes()) if batch.graph.out_degree(i)==0]
+            root_acc = np.sum(batch.label.asnumpy()[root_ids] == pred.asnumpy()[root_ids])
+            root_accs.append([root_acc, len(root_ids)])
+
+        dev_acc = 1.0*np.sum([x[0] for x in accs])/np.sum([x[1] for x in accs])
+        dev_root_acc = 1.0*np.sum([x[0] for x in root_accs])/np.sum([x[1] for x in root_accs])
+        print("Epoch {:05d} | Dev Acc {:.4f} | Root Acc {:.4f}".format(
+            epoch, dev_acc, dev_root_acc))
+
+        if dev_root_acc > best_dev_acc:
+            best_dev_acc = dev_root_acc
+            best_epoch = epoch
+            model.save_parameters('best_{}.params'.format(args.seed))
+        else:
+            if best_epoch <= epoch - 10:
+                break
+
+        # lr decay
+        trainer.set_learning_rate(max(1e-5, trainer.learning_rate*0.99))
+        print(trainer.learning_rate)
+        trainer_emb.set_learning_rate(max(1e-5, trainer_emb.learning_rate*0.99))
+        print(trainer_emb.learning_rate)
+
+    # test
+    model.load_parameters('best_{}.params'.format(args.seed))
+    accs = []
+    root_accs = []
+    for step, batch in enumerate(test_loader):
+        g = batch.graph
+        n = g.number_of_nodes()
+        h = mx.nd.zeros((n, args.h_size), ctx=ctx)
+        c = mx.nd.zeros((n, args.h_size), ctx=ctx)
+        pred = model(batch, h, c).argmax(axis=1)
+
+        acc = (batch.label == pred).sum().asscalar()
+        accs.append([acc, len(batch.label)])
+        root_ids = [i for i in range(batch.graph.number_of_nodes()) if batch.graph.out_degree(i)==0]
+        root_acc = np.sum(batch.label.asnumpy()[root_ids] == pred.asnumpy()[root_ids])
+        root_accs.append([root_acc, len(root_ids)])
+
+    test_acc = 1.0*np.sum([x[0] for x in accs])/np.sum([x[1] for x in accs])
+    test_root_acc = 1.0*np.sum([x[0] for x in root_accs])/np.sum([x[1] for x in root_accs])
+    print('------------------------------------------------------------------------------------')
+    print("Epoch {:05d} | Test Acc {:.4f} | Root Acc {:.4f}".format(
+        best_epoch, test_acc, test_root_acc))
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--gpu', type=int, default=0)
+    parser.add_argument('--seed', type=int, default=41)
+    parser.add_argument('--batch-size', type=int, default=256)
+    parser.add_argument('--child-sum', action='store_true')
+    parser.add_argument('--x-size', type=int, default=300)
+    parser.add_argument('--h-size', type=int, default=150)
+    parser.add_argument('--epochs', type=int, default=100)
+    parser.add_argument('--log-every', type=int, default=5)
+    parser.add_argument('--lr', type=float, default=0.05)
+    parser.add_argument('--weight-decay', type=float, default=1e-4)
+    parser.add_argument('--dropout', type=float, default=0.5)
+    parser.add_argument('--use-glove', action='store_true')
+    args = parser.parse_args()
+    print(args)
+    main(args)
diff --git a/examples/mxnet/tree_lstm/tree_lstm.py b/examples/mxnet/tree_lstm/tree_lstm.py
new file mode 100644
index 000000000000..f4c78d6bac71
--- /dev/null
+++ b/examples/mxnet/tree_lstm/tree_lstm.py
@@ -0,0 +1,129 @@
+"""
+Improved Semantic Representations From Tree-Structured Long Short-Term Memory Networks
+https://arxiv.org/abs/1503.00075
+"""
+import time
+import itertools
+import networkx as nx
+import numpy as np
+import mxnet as mx
+from mxnet import gluon
+import dgl
+
+class _TreeLSTMCellNodeFunc(gluon.HybridBlock):
+    def hybrid_forward(self, F, iou, b_iou, c):
+        iou = F.broadcast_add(iou, b_iou)
+        i, o, u = iou.split(num_outputs=3, axis=1)
+        i, o, u = i.sigmoid(), o.sigmoid(), u.tanh()
+        c = i * u + c
+        h = o * c.tanh()
+
+        return h, c
+
+class _TreeLSTMCellReduceFunc(gluon.HybridBlock):
+    def __init__(self, U_iou, U_f):
+        super(_TreeLSTMCellReduceFunc, self).__init__()
+        self.U_iou = U_iou
+        self.U_f = U_f
+
+    def hybrid_forward(self, F, h, c):
+        h_cat = h.reshape((0, -1))
+        f = self.U_f(h_cat).sigmoid().reshape_like(h)
+        c = (f * c).sum(axis=1)
+        iou = self.U_iou(h_cat)
+        return iou, c
+
+class _TreeLSTMCell(gluon.HybridBlock):
+    def __init__(self, h_size):
+        super(_TreeLSTMCell, self).__init__()
+        self._apply_node_func = _TreeLSTMCellNodeFunc()
+        self.b_iou = self.params.get('bias', shape=(1, 3 * h_size),
+                                     init='zeros')
+
+    def message_func(self, edges):
+        return {'h': edges.src['h'], 'c': edges.src['c']}
+
+    def apply_node_func(self, nodes):
+        iou = nodes.data['iou']
+        b_iou, c = self.b_iou.data(iou.context), nodes.data['c']
+        h, c = self._apply_node_func(iou, b_iou, c)
+        return {'h' : h, 'c' : c}
+
+class TreeLSTMCell(_TreeLSTMCell):
+    def __init__(self, x_size, h_size):
+        super(TreeLSTMCell, self).__init__(h_size)
+        self._reduce_func = _TreeLSTMCellReduceFunc(
+                gluon.nn.Dense(3 * h_size, use_bias=False),
+                gluon.nn.Dense(2 * h_size))
+        self.W_iou = gluon.nn.Dense(3 * h_size, use_bias=False)
+
+    def reduce_func(self, nodes):
+        h, c = nodes.mailbox['h'], nodes.mailbox['c']
+        iou, c = self._reduce_func(h, c)
+        return {'iou': iou, 'c': c}
+
+class ChildSumTreeLSTMCell(_TreeLSTMCell):
+    def __init__(self, x_size, h_size):
+        super(ChildSumTreeLSTMCell, self).__init__()
+        self.W_iou = gluon.nn.Dense(3 * h_size, use_bias=False)
+        self.U_iou = gluon.nn.Dense(3 * h_size, use_bias=False)
+        self.U_f = gluon.nn.Dense(h_size)
+
+    def reduce_func(self, nodes):
+        h_tild = nodes.mailbox['h'].sum(axis=1)
+        f = self.U_f(nodes.mailbox['h']).sigmoid()
+        c = (f * nodes.mailbox['c']).sum(axis=1)
+        return {'iou': self.U_iou(h_tild), 'c': c}
+
+class TreeLSTM(gluon.nn.Block):
+    def __init__(self,
+                 num_vocabs,
+                 x_size,
+                 h_size,
+                 num_classes,
+                 dropout,
+                 cell_type='nary',
+                 pretrained_emb=None,
+                 ctx=None):
+        super(TreeLSTM, self).__init__()
+        self.x_size = x_size
+        self.embedding = gluon.nn.Embedding(num_vocabs, x_size)
+        if pretrained_emb is not None:
+            print('Using glove')
+            self.embedding.initialize(ctx=ctx)
+            self.embedding.weight.set_data(pretrained_emb)
+        self.dropout = gluon.nn.Dropout(dropout)
+        self.linear = gluon.nn.Dense(num_classes)
+        cell = TreeLSTMCell if cell_type == 'nary' else ChildSumTreeLSTMCell
+        self.cell = cell(x_size, h_size)
+
+    def forward(self, batch, h, c):
+        """Compute tree-lstm prediction given a batch.
+        Parameters
+        ----------
+        batch : dgl.data.SSTBatch
+            The data batch.
+        h : Tensor
+            Initial hidden state.
+        c : Tensor
+            Initial cell state.
+        Returns
+        -------
+        logits : Tensor
+            The prediction of each node.
+        """
+        g = batch.graph
+        g.register_message_func(self.cell.message_func)
+        g.register_reduce_func(self.cell.reduce_func)
+        g.register_apply_node_func(self.cell.apply_node_func)
+        # feed embedding
+        embeds = self.embedding(batch.wordid * batch.mask)
+        g.ndata['iou'] = self.cell.W_iou(self.dropout(embeds)) * batch.mask.expand_dims(-1)
+        g.ndata['h'] = h
+        g.ndata['c'] = c
+        # propagate
+        dgl.prop_nodes_topo(g)
+        # compute logits
+        h = self.dropout(g.ndata.pop('h'))
+        logits = self.linear(h)
+        return logits
diff --git a/examples/pytorch/tree_lstm/train.py b/examples/pytorch/tree_lstm/train.py
index e1c013b88530..b8f9bcc73e59 100644
--- a/examples/pytorch/tree_lstm/train.py
+++ b/examples/pytorch/tree_lstm/train.py
@@ -9,7 +9,7 @@
 from torch.utils.data import DataLoader
 
 import dgl
-from dgl.data.tree import SST
+from dgl.data.tree import SST, SSTBatch
 
 from tree_lstm import TreeLSTM