diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe67863ca0..70685b2b1a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 All notable changes to `dash` will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## [UNRELEASED]
+### Added
+- [#1240](https://github.com/plotly/dash/pull/1240) Adds `callback_context` to clientside callbacks (e.g. `dash_clientside.callback_context.triggered`). Supports `triggered`, `inputs`, `inputs_list`, `states`, and `states_list`, all of which closely resemble their serverside cousins.
+
 ## [1.12.0] - 2020-05-05
 ### Added
 - [#1228](https://github.com/plotly/dash/pull/1228) Adds control over firing callbacks on page (or layout chunk) load. Individual callbacks can have their initial calls disabled in their definition `@app.callback(..., prevent_initial_call=True)` and similar for `app.clientside_callback`. The app-wide default can also be changed with `app=Dash(prevent_initial_callbacks=True)`, then individual callbacks may disable this behavior.
diff --git a/dash-renderer/src/actions/index.js b/dash-renderer/src/actions/index.js
index 83972f4bcc..05d0427381 100644
--- a/dash-renderer/src/actions/index.js
+++ b/dash-renderer/src/actions/index.js
@@ -525,6 +525,35 @@ const getVals = input =>
 
 const zipIfArray = (a, b) => (Array.isArray(a) ? zip(a, b) : [[a, b]]);
 
+function inputsToDict(inputs_list) {
+    // Ported directly from _utils.py, inputs_to_dict
+    // takes an array of inputs (some inputs may be an array)
+    // returns an Object (map):
+    //  keys of the form `id.property` or `{"id": 0}.property`
+    //  values contain the property value
+    if (!inputs_list) {
+        return {};
+    }
+    const inputs = {};
+    for (let i = 0; i < inputs_list.length; i++) {
+        if (Array.isArray(inputs_list[i])) {
+            const inputsi = inputs_list[i];
+            for (let ii = 0; ii < inputsi.length; ii++) {
+                const id_str = `${stringifyId(inputsi[ii].id)}.${
+                    inputsi[ii].property
+                }`;
+                inputs[id_str] = inputsi[ii].value ?? null;
+            }
+        } else {
+            const id_str = `${stringifyId(inputs_list[i].id)}.${
+                inputs_list[i].property
+            }`;
+            inputs[id_str] = inputs_list[i].value ?? null;
+        }
+    }
+    return inputs;
+}
+
 function handleClientside(clientside_function, payload) {
     const dc = (window.dash_clientside = window.dash_clientside || {});
     if (!dc.no_update) {
@@ -544,12 +573,26 @@ function handleClientside(clientside_function, payload) {
     let returnValue;
 
     try {
+        // setup callback context
+        const input_dict = inputsToDict(inputs);
+        dc.callback_context = {};
+        dc.callback_context.triggered = payload.changedPropIds.map(prop_id => ({
+            prop_id: prop_id,
+            value: input_dict[prop_id],
+        }));
+        dc.callback_context.inputs_list = inputs;
+        dc.callback_context.inputs = input_dict;
+        dc.callback_context.states_list = state;
+        dc.callback_context.states = inputsToDict(state);
+
         const {namespace, function_name} = clientside_function;
         let args = inputs.map(getVals);
         if (state) {
             args = concat(args, state.map(getVals));
         }
         returnValue = dc[namespace][function_name](...args);
+
+        delete dc.callback_context;
     } catch (e) {
         if (e === dc.PreventUpdate) {
             return {};
diff --git a/tests/integration/clientside/assets/clientside.js b/tests/integration/clientside/assets/clientside.js
index 067d7b4a1f..eaee0e6a09 100644
--- a/tests/integration/clientside/assets/clientside.js
+++ b/tests/integration/clientside/assets/clientside.js
@@ -56,6 +56,30 @@ window.dash_clientside.clientside = {
                 resolve('foo');
             }, 1);
         });
-    }
+    },
 
-}
+    triggered_to_str: function(n_clicks0, n_clicks1) {
+        const triggered = dash_clientside.callback_context.triggered;
+        return triggered.map(t => `${t.prop_id} = ${t.value}`).join(', ');
+    },
+
+    inputs_to_str: function(n_clicks0, n_clicks1) {
+        const inputs = dash_clientside.callback_context.inputs;
+        const keys = Object.keys(inputs);
+        return keys.map(k => `${k} = ${inputs[k]}`).join(', ');
+    },
+
+    inputs_list_to_str: function(n_clicks0, n_clicks1) {
+        return JSON.stringify(dash_clientside.callback_context.inputs_list);
+    },
+
+    states_to_str: function(val0, val1, st0, st1) {
+        const states = dash_clientside.callback_context.states;
+        const keys = Object.keys(states);
+        return keys.map(k => `${k} = ${states[k]}`).join(', ');
+    },
+
+    states_list_to_str: function(val0, val1, st0, st1) {
+        return JSON.stringify(dash_clientside.callback_context.states_list);
+    }
+};
diff --git a/tests/integration/clientside/test_clientside.py b/tests/integration/clientside/test_clientside.py
index 1b51fc4f43..f3239ba6bc 100644
--- a/tests/integration/clientside/test_clientside.py
+++ b/tests/integration/clientside/test_clientside.py
@@ -4,7 +4,8 @@
 import dash_html_components as html
 import dash_core_components as dcc
 from dash import Dash
-from dash.dependencies import Input, Output, State, ClientsideFunction
+from dash.dependencies import Input, Output, State, ClientsideFunction, ALL
+from selenium.webdriver.common.keys import Keys
 
 
 def test_clsd001_simple_clientside_serverside_callback(dash_duo):
@@ -365,3 +366,320 @@ def update_output(value):
     dash_duo.find_element("#input").send_keys("hello world")
     dash_duo.wait_for_text_to_equal("#output-serverside", 'Server says "hello world"')
     dash_duo.wait_for_text_to_equal("#output-clientside", 'Client says "hello world"')
+
+
+def test_clsd009_clientside_callback_context_triggered(dash_duo):
+    app = Dash(__name__, assets_folder="assets")
+
+    app.layout = html.Div(
+        [
+            html.Button("btn0", id="btn0"),
+            html.Button("btn1:0", id={"btn1": 0}),
+            html.Button("btn1:1", id={"btn1": 1}),
+            html.Button("btn1:2", id={"btn1": 2}),
+            html.Div(id="output-clientside", style={"font-family": "monospace"}),
+        ]
+    )
+
+    app.clientside_callback(
+        ClientsideFunction(namespace="clientside", function_name="triggered_to_str"),
+        Output("output-clientside", "children"),
+        [Input("btn0", "n_clicks"), Input({"btn1": ALL}, "n_clicks")],
+    )
+
+    dash_duo.start_server(app)
+
+    dash_duo.wait_for_text_to_equal("#output-clientside", "")
+
+    dash_duo.find_element("#btn0").click()
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside", "btn0.n_clicks = 1",
+    )
+
+    dash_duo.find_element("button[id*='btn1\":0']").click()
+    dash_duo.find_element("button[id*='btn1\":0']").click()
+
+    dash_duo.wait_for_text_to_equal("#output-clientside", '{"btn1":0}.n_clicks = 2')
+
+    dash_duo.find_element("button[id*='btn1\":2']").click()
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside", '{"btn1":2}.n_clicks = 1',
+    )
+
+
+def test_clsd010_clientside_callback_context_inputs(dash_duo):
+    app = Dash(__name__, assets_folder="assets")
+
+    app.layout = html.Div(
+        [
+            html.Button("btn0", id="btn0"),
+            html.Button("btn1:0", id={"btn1": 0}),
+            html.Button("btn1:1", id={"btn1": 1}),
+            html.Button("btn1:2", id={"btn1": 2}),
+            html.Div(id="output-clientside", style={"font-family": "monospace"}),
+        ]
+    )
+
+    app.clientside_callback(
+        ClientsideFunction(namespace="clientside", function_name="inputs_to_str"),
+        Output("output-clientside", "children"),
+        [Input("btn0", "n_clicks"), Input({"btn1": ALL}, "n_clicks")],
+    )
+
+    dash_duo.start_server(app)
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            "btn0.n_clicks = null, "
+            '{"btn1":0}.n_clicks = null, '
+            '{"btn1":1}.n_clicks = null, '
+            '{"btn1":2}.n_clicks = null'
+        ),
+    )
+
+    dash_duo.find_element("#btn0").click()
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            "btn0.n_clicks = 1, "
+            '{"btn1":0}.n_clicks = null, '
+            '{"btn1":1}.n_clicks = null, '
+            '{"btn1":2}.n_clicks = null'
+        ),
+    )
+
+    dash_duo.find_element("button[id*='btn1\":0']").click()
+    dash_duo.find_element("button[id*='btn1\":0']").click()
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            "btn0.n_clicks = 1, "
+            '{"btn1":0}.n_clicks = 2, '
+            '{"btn1":1}.n_clicks = null, '
+            '{"btn1":2}.n_clicks = null'
+        ),
+    )
+
+    dash_duo.find_element("button[id*='btn1\":2']").click()
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            "btn0.n_clicks = 1, "
+            '{"btn1":0}.n_clicks = 2, '
+            '{"btn1":1}.n_clicks = null, '
+            '{"btn1":2}.n_clicks = 1'
+        ),
+    )
+
+
+def test_clsd011_clientside_callback_context_inputs_list(dash_duo):
+    app = Dash(__name__, assets_folder="assets")
+
+    app.layout = html.Div(
+        [
+            html.Button("btn0", id="btn0"),
+            html.Button("btn1:0", id={"btn1": 0}),
+            html.Button("btn1:1", id={"btn1": 1}),
+            html.Button("btn1:2", id={"btn1": 2}),
+            html.Div(id="output-clientside", style={"font-family": "monospace"}),
+        ]
+    )
+
+    app.clientside_callback(
+        ClientsideFunction(namespace="clientside", function_name="inputs_list_to_str"),
+        Output("output-clientside", "children"),
+        [Input("btn0", "n_clicks"), Input({"btn1": ALL}, "n_clicks")],
+    )
+
+    dash_duo.start_server(app)
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            '[{"id":"btn0","property":"n_clicks"},'
+            '[{"id":{"btn1":0},"property":"n_clicks"},'
+            '{"id":{"btn1":1},"property":"n_clicks"},'
+            '{"id":{"btn1":2},"property":"n_clicks"}]]'
+        ),
+    )
+
+    dash_duo.find_element("#btn0").click()
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            '[{"id":"btn0","property":"n_clicks","value":1},'
+            '[{"id":{"btn1":0},"property":"n_clicks"},'
+            '{"id":{"btn1":1},"property":"n_clicks"},'
+            '{"id":{"btn1":2},"property":"n_clicks"}]]'
+        ),
+    )
+
+    dash_duo.find_element("button[id*='btn1\":0']").click()
+    dash_duo.find_element("button[id*='btn1\":0']").click()
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            '[{"id":"btn0","property":"n_clicks","value":1},'
+            '[{"id":{"btn1":0},"property":"n_clicks","value":2},'
+            '{"id":{"btn1":1},"property":"n_clicks"},'
+            '{"id":{"btn1":2},"property":"n_clicks"}]]'
+        ),
+    )
+
+    dash_duo.find_element("button[id*='btn1\":2']").click()
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            '[{"id":"btn0","property":"n_clicks","value":1},'
+            '[{"id":{"btn1":0},"property":"n_clicks","value":2},'
+            '{"id":{"btn1":1},"property":"n_clicks"},'
+            '{"id":{"btn1":2},"property":"n_clicks","value":1}]]'
+        ),
+    )
+
+
+def test_clsd012_clientside_callback_context_states(dash_duo):
+    app = Dash(__name__, assets_folder="assets")
+
+    app.layout = html.Div(
+        [
+            dcc.Input(id="in0"),
+            dcc.Input(id={"in1": 0}),
+            dcc.Input(id={"in1": 1}),
+            dcc.Input(id={"in1": 2}),
+            html.Div(id="output-clientside", style={"font-family": "monospace"}),
+        ]
+    )
+
+    app.clientside_callback(
+        ClientsideFunction(namespace="clientside", function_name="states_to_str"),
+        Output("output-clientside", "children"),
+        [Input("in0", "n_submit"), Input({"in1": ALL}, "n_submit")],
+        [State("in0", "value"), State({"in1": ALL}, "value")],
+    )
+
+    dash_duo.start_server(app)
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            "in0.value = null, "
+            '{"in1":0}.value = null, '
+            '{"in1":1}.value = null, '
+            '{"in1":2}.value = null'
+        ),
+    )
+
+    dash_duo.find_element("#in0").send_keys("test 0" + Keys.RETURN)
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            "in0.value = test 0, "
+            '{"in1":0}.value = null, '
+            '{"in1":1}.value = null, '
+            '{"in1":2}.value = null'
+        ),
+    )
+
+    dash_duo.find_element("input[id*='in1\":0']").send_keys("test 1" + Keys.RETURN)
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            "in0.value = test 0, "
+            '{"in1":0}.value = test 1, '
+            '{"in1":1}.value = null, '
+            '{"in1":2}.value = null'
+        ),
+    )
+
+    dash_duo.find_element("input[id*='in1\":2']").send_keys("test 2" + Keys.RETURN)
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            "in0.value = test 0, "
+            '{"in1":0}.value = test 1, '
+            '{"in1":1}.value = null, '
+            '{"in1":2}.value = test 2'
+        ),
+    )
+
+
+def test_clsd013_clientside_callback_context_states_list(dash_duo):
+    app = Dash(__name__, assets_folder="assets")
+
+    app.layout = html.Div(
+        [
+            dcc.Input(id="in0"),
+            dcc.Input(id={"in1": 0}),
+            dcc.Input(id={"in1": 1}),
+            dcc.Input(id={"in1": 2}),
+            html.Div(id="output-clientside", style={"font-family": "monospace"}),
+        ]
+    )
+
+    app.clientside_callback(
+        ClientsideFunction(namespace="clientside", function_name="states_list_to_str"),
+        Output("output-clientside", "children"),
+        [Input("in0", "n_submit"), Input({"in1": ALL}, "n_submit")],
+        [State("in0", "value"), State({"in1": ALL}, "value")],
+    )
+
+    dash_duo.start_server(app)
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            '[{"id":"in0","property":"value"},'
+            '[{"id":{"in1":0},"property":"value"},'
+            '{"id":{"in1":1},"property":"value"},'
+            '{"id":{"in1":2},"property":"value"}]]'
+        ),
+    )
+
+    dash_duo.find_element("#in0").send_keys("test 0" + Keys.RETURN)
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            '[{"id":"in0","property":"value","value":"test 0"},'
+            '[{"id":{"in1":0},"property":"value"},'
+            '{"id":{"in1":1},"property":"value"},'
+            '{"id":{"in1":2},"property":"value"}]]'
+        ),
+    )
+
+    dash_duo.find_element("input[id*='in1\":0']").send_keys("test 1" + Keys.RETURN)
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            '[{"id":"in0","property":"value","value":"test 0"},'
+            '[{"id":{"in1":0},"property":"value","value":"test 1"},'
+            '{"id":{"in1":1},"property":"value"},'
+            '{"id":{"in1":2},"property":"value"}]]'
+        ),
+    )
+
+    dash_duo.find_element("input[id*='in1\":2']").send_keys("test 2" + Keys.RETURN)
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        (
+            '[{"id":"in0","property":"value","value":"test 0"},'
+            '[{"id":{"in1":0},"property":"value","value":"test 1"},'
+            '{"id":{"in1":1},"property":"value"},'
+            '{"id":{"in1":2},"property":"value","value":"test 2"}]]'
+        ),
+    )