diff --git a/packages/controls/src/index.ts b/packages/controls/src/index.ts
index 912458d981..bb77d10b2a 100644
--- a/packages/controls/src/index.ts
+++ b/packages/controls/src/index.ts
@@ -23,5 +23,6 @@ export * from './widget_tagsinput';
 export * from './widget_string';
 export * from './widget_description';
 export * from './widget_upload';
+export * from './widget_fieldset';
 
 export const version = (require('../package.json') as any).version;
diff --git a/packages/controls/src/widget_fieldset.ts b/packages/controls/src/widget_fieldset.ts
new file mode 100644
index 0000000000..4f858b1bec
--- /dev/null
+++ b/packages/controls/src/widget_fieldset.ts
@@ -0,0 +1,127 @@
+// Copyright (c) Jupyter Development Team.
+// Distributed under the terms of the Modified BSD License.
+
+import {
+    DOMWidgetView,
+    unpack_models,
+    ViewList,
+    JupyterLuminoPanelWidget,
+    reject,
+    WidgetModel,
+    WidgetView,
+} from '@jupyter-widgets/base';
+
+import { CoreDOMWidgetModel } from './widget_core';
+
+import { ArrayExt } from '@lumino/algorithm';
+
+import { MessageLoop } from '@lumino/messaging';
+
+import { Widget } from '@lumino/widgets';
+
+import $ from 'jquery';
+
+export class FieldsetModel extends CoreDOMWidgetModel {
+    defaults(): Backbone.ObjectHash {
+        return {
+            ...super.defaults(),
+            _view_name: 'FieldsetView',
+            _model_name: 'FieldsetModel',
+            children: [],
+            box_style: '',
+        };
+    }
+
+    static serializers = {
+        ...CoreDOMWidgetModel.serializers,
+        children: { deserialize: unpack_models },
+    };
+}
+
+
+export class FieldsetView extends DOMWidgetView {
+    _createElement(tagName: string): HTMLElement {
+        this.luminoWidget = new JupyterLuminoPanelWidget({ view: this });
+        return this.luminoWidget.node;
+    }
+
+    _setElement(el: HTMLElement): void {
+        if (this.el || el !== this.luminoWidget.node) {
+            // Boxes don't allow setting the element beyond the initial creation.
+            throw new Error('Cannot reset the DOM element.');
+        }
+
+        this.el = this.luminoWidget.node;
+        this.$el = $(this.luminoWidget.node);
+    }
+
+    initialize(parameters: WidgetView.IInitializeParameters): void {
+        super.initialize(parameters);
+        this.children_views = new ViewList(this.add_child_model, null, this);
+        this.listenTo(this.model, 'change:children', this.update_children);
+        this.listenTo(this.model, 'change:fieldset_style', this.update_fieldset_style);
+
+        this.luminoWidget.addClass('jupyter-widgets');
+        this.luminoWidget.addClass('widget-container');
+    }
+
+    render(): void {
+        super.render();
+        this.update_children();
+        this.set_fieldset_style();
+    }
+
+    update_children(): void {
+        this.children_views
+            ?.update(this.model.get('children'))
+            .then((views: DOMWidgetView[]) => {
+                // Notify all children that their sizes may have changed.
+                views.forEach((view) => {
+                    MessageLoop.postMessage(
+                        view.luminoWidget,
+                        Widget.ResizeMessage.UnknownSize
+                    );
+                });
+            });
+    }
+
+    update_fieldset_style(): void {
+        this.update_mapped_classes(FieldsetView.class_map, 'fieldset_style');
+    }
+
+    set_fieldset_style(): void {
+        this.set_mapped_classes(FieldsetView.class_map, 'fieldset_style');
+    }
+
+    add_child_model(model: WidgetModel): Promise<DOMWidgetView> {
+        // we insert a dummy element so the order is preserved when we add
+        // the rendered content later.
+        const dummy = new Widget();
+        this.luminoWidget.addWidget(dummy);
+
+        return this.create_child_view(model)
+            .then((view: DOMWidgetView) => {
+                // replace the dummy widget with the new one.
+                const i = ArrayExt.firstIndexOf(this.luminoWidget.widgets, dummy);
+                this.luminoWidget.insertWidget(i, view.luminoWidget);
+                dummy.dispose();
+                return view;
+            })
+            .catch(reject('Could not add child view to fieldset', true));
+    }
+
+    remove(): void {
+        this.children_views = null;
+        super.remove();
+    }
+
+    children_views: ViewList<DOMWidgetView> | null;
+    luminoWidget: JupyterLuminoPanelWidget;
+
+    static class_map = {
+        success: ['alert', 'alert-success'],
+        info: ['alert', 'alert-info'],
+        warning: ['alert', 'alert-warning'],
+        danger: ['alert', 'alert-danger'],
+    };
+}
diff --git a/python/ipywidgets/ipywidgets/widgets/__init__.py b/python/ipywidgets/ipywidgets/widgets/__init__.py
index b90d3ee111..69a4a8a9d0 100644
--- a/python/ipywidgets/ipywidgets/widgets/__init__.py
+++ b/python/ipywidgets/ipywidgets/widgets/__init__.py
@@ -11,18 +11,48 @@
 from .widget_bool import Checkbox, ToggleButton, Valid
 from .widget_button import Button, ButtonStyle
 from .widget_box import Box, HBox, VBox, GridBox
-from .widget_float import FloatText, BoundedFloatText, FloatSlider, FloatProgress, FloatRangeSlider, FloatLogSlider
-from .widget_int import IntText, BoundedIntText, IntSlider, IntProgress, IntRangeSlider, Play, SliderStyle
+from .widget_float import (
+    FloatText,
+    BoundedFloatText,
+    FloatSlider,
+    FloatProgress,
+    FloatRangeSlider,
+    FloatLogSlider,
+)
+from .widget_int import (
+    IntText,
+    BoundedIntText,
+    IntSlider,
+    IntProgress,
+    IntRangeSlider,
+    Play,
+    SliderStyle,
+)
 from .widget_color import ColorPicker
 from .widget_date import DatePicker
 from .widget_datetime import DatetimePicker, NaiveDatetimePicker
 from .widget_time import TimePicker
 from .widget_output import Output
-from .widget_selection import RadioButtons, ToggleButtons, ToggleButtonsStyle, Dropdown, Select, SelectionSlider, SelectMultiple, SelectionRangeSlider
-from .widget_selectioncontainer import Tab, Accordion, Stack
+from .widget_selection import (
+    RadioButtons,
+    ToggleButtons,
+    ToggleButtonsStyle,
+    Dropdown,
+    Select,
+    SelectionSlider,
+    SelectMultiple,
+    SelectionRangeSlider,
+)
+from .....branches.widget_selectioncontainer import Tab, Accordion, Stack
 from .widget_string import HTML, HTMLMath, Label, Text, Textarea, Password, Combobox
 from .widget_controller import Controller
-from .interaction import interact, interactive, fixed, interact_manual, interactive_output
+from .interaction import (
+    interact,
+    interactive,
+    fixed,
+    interact_manual,
+    interactive_output,
+)
 from .widget_link import jslink, jsdlink
 from .widget_layout import Layout
 from .widget_media import Image, Video, Audio
@@ -30,3 +60,4 @@
 from .widget_style import Style
 from .widget_templates import TwoByTwoLayout, AppLayout, GridspecLayout
 from .widget_upload import FileUpload
+from .widget_fieldset import Fieldset
diff --git a/python/ipywidgets/ipywidgets/widgets/widget_fieldset.py b/python/ipywidgets/ipywidgets/widgets/widget_fieldset.py
new file mode 100644
index 0000000000..4c483d557f
--- /dev/null
+++ b/python/ipywidgets/ipywidgets/widgets/widget_fieldset.py
@@ -0,0 +1,68 @@
+# Copyright (c) Jupyter Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+"""Fieldset widget.
+
+This widget is used to group other control widgets into a fieldset.
+"""
+
+from .widget import register, widget_serialization, Widget
+from .domwidget import DOMWidget
+from .widget_core import CoreWidget
+from .docutils import doc_subst
+from .trait_types import TypedTuple
+from traitlets import Unicode, CaselessStrEnum, Instance
+
+
+_doc_snippets = {}
+_doc_snippets[
+    "box_params"
+] = """
+    children: iterable of Widget instances
+        list of widgets to display
+
+    box_style: str
+        one of 'success', 'info', 'warning' or 'danger', or ''.
+        Applies a predefined style to the box. Defaults to '',
+        which applies no pre-defined style.
+"""
+
+
+@register
+@doc_subst(_doc_snippets)
+class Fieldset(DOMWidget, CoreWidget):
+    """Displays controls grouped together, optionally with a caption.
+
+    The widgets are laid out horizontally.
+
+    Parameters
+    ----------
+    {box_params}
+
+    Examples
+    --------
+    >>> import ipywidgets as widgets
+    >>> slider = widgets.IntSlider()
+    >>> widgets.Fieldset(legend="Fieldset Example", children=[slider])
+    """
+
+    _model_name = Unicode("FieldsetModel").tag(sync=True)
+    _view_name = Unicode("FieldsetView").tag(sync=True)
+
+    # Child widgets in the container.
+    # Using a tuple here to force reassignment to update the list.
+    # When a proper notifying-list trait exists, use that instead.
+    children = TypedTuple(trait=Instance(Widget), help="List of widget children").tag(
+        sync=True, **widget_serialization
+    )
+
+    box_style = CaselessStrEnum(
+        values=["success", "info", "warning", "danger", ""],
+        default_value="",
+        help="""Use a predefined styling for the box.""",
+    ).tag(sync=True)
+
+    def __init__(self, legend="", children=(), **kwargs):
+        kwargs["legend"] = legend
+        kwargs["children"] = children
+        super().__init__(**kwargs)