diff --git a/addons/web/controllers/main.py b/addons/web/controllers/main.py
index 930a8233eb5..479b74a19d4 100644
--- a/addons/web/controllers/main.py
+++ b/addons/web/controllers/main.py
@@ -1023,27 +1023,31 @@ class Binary(http.Controller):
     @http.route('/web/binary/upload_attachment', type='http', auth="user")
     @serialize_exception
     def upload_attachment(self, callback, model, id, ufile):
+        files = request.httprequest.files.getlist('ufile')
         Model = request.env['ir.attachment']
         out = """<script language="javascript" type="text/javascript">
                     var win = window.top.window;
                     win.jQuery(win).trigger(%s, %s);
                 </script>"""
-        try:
-            attachment = Model.create({
-                'name': ufile.filename,
-                'datas': base64.encodestring(ufile.read()),
-                'datas_fname': ufile.filename,
-                'res_model': model,
-                'res_id': int(id)
-            })
-            args = {
-                'filename': ufile.filename,
-                'mimetype': ufile.content_type,
-                'id':  attachment.id
-            }
-        except Exception:
-            args = {'error': _("Something horrible happened")}
-            _logger.exception("Fail to upload attachment %s" % ufile.filename)
+        args = []
+        for ufile in files:
+            try:
+                attachment = Model.create({
+                    'name': ufile.filename,
+                    'datas': base64.encodestring(ufile.read()),
+                    'datas_fname': ufile.filename,
+                    'res_model': model,
+                    'res_id': int(id)
+                })
+            except Exception:
+                args = args.append({'error': _("Something horrible happened")})
+                _logger.exception("Fail to upload attachment %s" % ufile.filename)
+            else:
+                args.append({
+                    'filename': ufile.filename,
+                    'mimetype': ufile.content_type,
+                    'id': attachment.id
+                })
         return out % (json.dumps(callback), json.dumps(args))
 
     @http.route([
diff --git a/addons/web/static/src/js/views/form_relational_widgets.js b/addons/web/static/src/js/views/form_relational_widgets.js
index a15b588a297..b95b708aa05 100644
--- a/addons/web/static/src/js/views/form_relational_widgets.js
+++ b/addons/web/static/src/js/views/form_relational_widgets.js
@@ -1534,43 +1534,27 @@ var FieldMany2ManyBinaryMultiFiles = AbstractManyField.extend(common.Reinitializ
         'click .o_attach': function(e) {
             this.$('.o_form_input_file').click();
         },
-        'change .o_form_input_file': function(e) {
-            e.stopPropagation();
+        'change .o_form_input_file': function(event) {
+            event.stopPropagation();
+            var files = event.target.files,
+                attachments = this.get('value');
 
-            var $target = $(e.target);
-            var value = $target.val();
-
-            if(value !== '') {
-                if(this.data[0] && this.data[0].upload) { // don't upload more of one file in same time
-                    return false;
-                }
-
-                var filename = value.replace(/.*[\\\/]/, '');
-                for(var id in this.get('value')) {
-                    // if the files exits, delete the file before upload (if it's a new file)
-                    if(this.data[id] && (this.data[id].filename || this.data[id].name) == filename && !this.data[id].no_unlink) {
-                        this.ds_file.unlink([id]);
-                    }
-                }
-
-                if(this.node.attrs.blockui > 0) { // block UI or not
-                    framework.blockUI();
-                }
-
-                // TODO : unactivate send on wizard and form
-
-                // submit file
-                this.$('form.o_form_binary_form').submit();
-                this.$(".oe_fileupload").hide();
-                // add file on data result
-                this.data[0] = {
-                    id: 0,
-                    name: filename,
-                    filename: filename,
-                    url: '',
-                    upload: true,
-                };
+            if(this.node.attrs.blockui){
+                framework.blockUI();
             }
+            _.each(files, function(file){
+                var attachment = _.findWhere(_.values(this.data), {filename: file.name});
+                if(attachment && !attachment.no_unlink){
+                    this.ds_file.unlink([attachment.id]);
+                    attachments = _.without(attachments, attachment.id);
+                    this.data = _.omit(this.data, attachment.id);
+                }
+                this.files_uploading.push(file);
+            }.bind(this));
+            this.set({value: attachments});
+            this.$('form.o_form_binary_form').submit();
+            this.$(".oe_fileupload").hide();
+            this.render_value();
         },
         'click .oe_delete': function(e) {
             e.preventDefault();
@@ -1581,6 +1565,7 @@ var FieldMany2ManyBinaryMultiFiles = AbstractManyField.extend(common.Reinitializ
                 var files = _.without(this.get('value'), file_id);
                 if(!this.data[file_id].no_unlink) {
                     this.ds_file.unlink([file_id]);
+                    this.data = _.omit(this.data, file_id);
                 }
                 this.set({'value': files});
             }
@@ -1593,6 +1578,7 @@ var FieldMany2ManyBinaryMultiFiles = AbstractManyField.extend(common.Reinitializ
             throw _.str.sprintf(_t("The type of the field '%s' must be a many2many field with a relation to 'ir.attachment' model."), this.field.string);
         }
         this.data = {};
+        this.files_uploading = [];
         this.set_value([]);
         this.ds_file = new data.DataSetSearch(this, 'ir.attachment');
         this.fileupload_id = _.uniqueId('oe_fileupload_temp');
@@ -1628,10 +1614,6 @@ var FieldMany2ManyBinaryMultiFiles = AbstractManyField.extend(common.Reinitializ
         this.read_name_values().then(function (ids) {
             self.$('.oe_placeholder_files, .oe_attachments')
                 .replaceWith($(QWeb.render('FieldBinaryFileUploader.files', {'widget': self, 'values': ids})));
-
-            // reinit input type file
-            var $input = self.$('.o_form_input_file');
-            $input.after($input.clone(true)).remove();
             self.$(".oe_fileupload").show();
 
             // display image thumbnail
@@ -1644,23 +1626,25 @@ var FieldMany2ManyBinaryMultiFiles = AbstractManyField.extend(common.Reinitializ
         });
     },
     on_file_loaded: function(e, result) {
-        if(this.node.attrs.blockui > 0) { // unblock UI
+        var attachments = this.get('value'),
+            files = Array.prototype.slice.call(arguments, 1);
+            this.files_uploading = []; // files has been uploaded clear uploading
+
+        if(this.node.attrs.blockui) { // unblock UI
             framework.unblockUI();
         }
-
-        if(result.error || !result.id) {
-            this.do_warn(_t('Uploading Error'), result.error);
-            delete this.data[0];
-        } else {
-            if(this.data[0] && this.data[0].filename === result.filename && this.data[0].upload) {
-                delete this.data[0];
-            }
-            result.url = this.get_file_url(result);
-            this.data[result.id] = result;
-            var values = _.clone(this.get('value'));
-            values.push(result.id);
-            this.set({value: values});
+        var upload_error = _.filter(files, function(attachment) {return attachment.error;});
+        if (upload_error.length) {
+            this.do_warn(_t('Uploading Error'), upload_error[0].error);
         }
+        _.each(files, function(file){
+            if(!file.error){
+                attachments.push(file.id);
+                file.url = this.get_file_url(file);
+                this.data[file.id] = file;
+            }
+        }.bind(this));
+        this.set({value: _.clone(attachments)});
         this.render_value();
     },
 });
diff --git a/addons/web/static/src/js/widgets/sidebar.js b/addons/web/static/src/js/widgets/sidebar.js
index 1e382c3d985..32513048087 100644
--- a/addons/web/static/src/js/widgets/sidebar.js
+++ b/addons/web/static/src/js/widgets/sidebar.js
@@ -170,8 +170,9 @@ var Sidebar = Widget.extend({
     do_attachement_update: function(dataset, model_id, args) {
         this.dataset = dataset;
         this.model_id = model_id;
-        if (args && args[0].error) {
-            this.do_warn(_t('Uploading Error'), args[0].error);
+        var upload_error = _.filter(args, function(attachment) {return attachment.error;});
+        if (upload_error.length) {
+            this.do_warn(_t('Uploading Error'), upload_error[0].error);
         }
         if (!model_id) {
             this.on_attachments_loaded([]);
diff --git a/addons/web/static/src/xml/base.xml b/addons/web/static/src/xml/base.xml
index dc3119908fe..f6ac60c4d7e 100644
--- a/addons/web/static/src/xml/base.xml
+++ b/addons/web/static/src/xml/base.xml
@@ -244,6 +244,7 @@
                     <t t-call="HiddenInputFile">
                         <t t-set="fileupload_id" t-value="widget.fileupload_id"/>
                         <t t-set="fileupload_action" t-translation="off">/web/binary/upload_attachment</t>
+                        <t t-set="multi_upload" t-value="true"/>
                         <input type="hidden" name="model" t-att-value="widget.dataset and widget.dataset.model"/>
                         <input type="hidden" name="id" t-att-value="widget.model_id"/>
                         <input type="hidden" name="session_id" t-att-value="widget.session.session_id" t-if="widget.session.override_session"/>
@@ -1003,7 +1004,7 @@
             <input type="hidden" name="csrf_token" t-att-value="csrf_token"/>
             <input type="hidden" name="session_id" value="" t-if="widget.session.override_session"/>
             <input type="hidden" name="callback" t-att-value="fileupload_id"/>
-            <input t-if="widget.widget!='image'" type="file" class="o_form_input_file" name="ufile"/>
+            <input t-if="widget.widget!='image'" type="file" class="o_form_input_file" name="ufile" t-att="{'multiple': multi_upload ? 'multiple' : null}"/>
             <input t-if="widget.widget=='image'" type="file" class="o_form_input_file" name="ufile" accept="image/*"/>
             <t t-raw="0"/>
         </form>
@@ -1017,6 +1018,7 @@
         <t t-call="HiddenInputFile">
             <t t-set="fileupload_id" t-value="widget.fileupload_id"/>
             <t t-set="fileupload_action" t-translation="off">/web/binary/upload_attachment</t>
+            <t t-set="multi_upload" t-value="true"/>
             <input type="hidden" name="model" t-att-value="widget.view.model"/>
             <input type="hidden" name="id" value="0"/>
             <input t-if="widget.session.override_session" type="hidden" name="session_id" t-att-value="widget.session.session_id"/>
@@ -1033,23 +1035,24 @@
     <t t-if="!widget.get('effective_readonly')">
         <div t-foreach="values" t-as="id" class="oe_attachment">
             <t t-set="file" t-value="widget.data[id]"/>
-            <span t-if="file.upload or file.percent_loaded&lt;100"
-                  t-att-title="(file.name || file.filename) + ((file.date)? (' \n(' + file.date + ')') : '')"
-                  t-att-name="file.name || file.filename">
-                <span class="oe_fileuploader_in_process">...Upload in progress...</span>
-                <t t-raw="file.name || file.filename"/>
-            </span>
-            <t t-if="!file.upload or file.percent_loaded&gt;=100">
+            <t t-if="!file.upload">
                 <div>
                     <a href="#" class="fa fa-times pull-right oe_delete" title="Delete this file" t-att-data-id="file.id"/>
                     <t t-raw="file.name || file.filename"/>
                 </div>
                 <a class="o_image" target="_blank" t-att-href="file.url"
-                   t-att-title="(file.name || file.filename) + ((file.date)? (' \n(' + file.date + ')') : '')"
+                   t-att-title="file.name"
                    t-att-data-mimetype="file.mimetype"
                    t-attf-data-src="/web/image/#{file.id}/100x80"/>
             </t>
         </div>
+        <div t-foreach="widget.files_uploading" t-as="file" class="oe_attachment">
+            <div>Uploading...</div>
+            <a t-att-title="file.name" t-att-name="file.name" class="o_image">
+                <i class="fa fa-spinner fa-spin fa-5x fa-fw"></i>
+            </a>
+            <div><t t-esc="file.name"/></div>
+        </div>
     </t>
 </div>
 <div t-name="SearchView" class="o_searchview">