diff --git a/browser/devtools/shared/test/browser.ini b/browser/devtools/shared/test/browser.ini
index b5da569d9686..312b121b7a87 100644
--- a/browser/devtools/shared/test/browser.ini
+++ b/browser/devtools/shared/test/browser.ini
@@ -27,6 +27,9 @@ support-files =
 [browser_filter-editor-05.js]
 [browser_filter-editor-06.js]
 [browser_filter-editor-07.js]
+[browser_filter-editor-08.js]
+[browser_filter-editor-09.js]
+[browser_filter-editor-10.js]
 [browser_flame-graph-01.js]
 [browser_flame-graph-02.js]
 [browser_flame-graph-03a.js]
diff --git a/browser/devtools/shared/test/browser_filter-editor-08.js b/browser/devtools/shared/test/browser_filter-editor-08.js
new file mode 100644
index 000000000000..f041419a9f7c
--- /dev/null
+++ b/browser/devtools/shared/test/browser_filter-editor-08.js
@@ -0,0 +1,82 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Tests the Filter Editor Widget inputs increase/decrease value using
+// arrow keys, applying multiplier using alt/shift on number-type filters
+
+const TEST_URI = "chrome://browser/content/devtools/filter-frame.xhtml";
+const {CSSFilterEditorWidget} = require("devtools/shared/widgets/FilterWidget");
+
+const FAST_VALUE_MULTIPLIER = 10;
+const SLOW_VALUE_MULTIPLIER = 0.1;
+const DEFAULT_VALUE_MULTIPLIER = 1;
+
+add_task(function*() {
+  yield promiseTab("about:blank");
+  let [host, win, doc] = yield createHost("bottom", TEST_URI);
+
+  const container = doc.querySelector("#container");
+  const initialValue = "blur(2px)";
+  let widget = new CSSFilterEditorWidget(container, initialValue);
+
+  let value = 2;
+
+  triggerKey = triggerKey.bind(widget);
+
+  info("Test simple arrow keys");
+  triggerKey(40);
+
+  value -= DEFAULT_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), `${value}px`,
+     "Should decrease value using down arrow");
+
+  triggerKey(38);
+
+  value += DEFAULT_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), `${value}px`,
+     "Should decrease value using down arrow");
+
+  info("Test shift key multiplier");
+  triggerKey(38, "shiftKey");
+
+  value += FAST_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), `${value}px`,
+     "Should increase value by fast multiplier using up arrow");
+
+  triggerKey(40, "shiftKey");
+
+  value -= FAST_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), `${value}px`,
+     "Should decrease value by fast multiplier using down arrow");
+
+  info("Test alt key multiplier");
+  triggerKey(38, "altKey");
+
+  value += SLOW_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), `${value}px`,
+     "Should increase value by slow multiplier using up arrow");
+
+  triggerKey(40, "altKey");
+
+  value -= SLOW_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), `${value}px`,
+     "Should decrease value by slow multiplier using down arrow");
+
+  triggerKey = null;
+});
+
+// Triggers the specified keyCode and modifier key on
+// first filter's input
+function triggerKey(key, modifier) {
+  const filter = this.el.querySelector(".filters").children[0];
+  const input = filter.querySelector("input");
+
+  this._keyDown({
+    target: input,
+    keyCode: key,
+    [modifier]: true,
+    preventDefault: function() {}
+  });
+}
diff --git a/browser/devtools/shared/test/browser_filter-editor-09.js b/browser/devtools/shared/test/browser_filter-editor-09.js
new file mode 100644
index 000000000000..f3d6b7c01ffe
--- /dev/null
+++ b/browser/devtools/shared/test/browser_filter-editor-09.js
@@ -0,0 +1,123 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Tests the Filter Editor Widget inputs increase/decrease value when cursor is
+// on a number using arrow keys, applying multiplier using alt/shift on strings
+
+const TEST_URI = "chrome://browser/content/devtools/filter-frame.xhtml";
+const {CSSFilterEditorWidget} = require("devtools/shared/widgets/FilterWidget");
+
+const FAST_VALUE_MULTIPLIER = 10;
+const SLOW_VALUE_MULTIPLIER = 0.1;
+const DEFAULT_VALUE_MULTIPLIER = 1;
+
+add_task(function*() {
+  yield promiseTab("about:blank");
+  let [host, win, doc] = yield createHost("bottom", TEST_URI);
+
+  const container = doc.querySelector("#container");
+  const initialValue = "drop-shadow(rgb(0, 0, 0) 1px 1px 0px)";
+  let widget = new CSSFilterEditorWidget(container, initialValue);
+  widget.el.querySelector("input").setSelectionRange(13, 13);
+
+  let value = 1;
+
+  triggerKey = triggerKey.bind(widget);
+
+  info("Test simple arrow keys");
+  triggerKey(40);
+
+  value -= DEFAULT_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should decrease value using down arrow");
+
+  triggerKey(38);
+
+  value += DEFAULT_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should decrease value using down arrow");
+
+  info("Test shift key multiplier");
+  triggerKey(38, "shiftKey");
+
+  value += FAST_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should increase value by fast multiplier using up arrow");
+
+  triggerKey(40, "shiftKey");
+
+  value -= FAST_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should decrease value by fast multiplier using down arrow");
+
+  info("Test alt key multiplier");
+  triggerKey(38, "altKey");
+
+  value += SLOW_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should increase value by slow multiplier using up arrow");
+
+  triggerKey(40, "altKey");
+
+  value -= SLOW_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should decrease value by slow multiplier using down arrow");
+
+  triggerKey(40, "shiftKey");
+
+  value -= FAST_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should decrease to negative");
+
+  triggerKey(40);
+
+  value -= DEFAULT_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should decrease negative numbers correctly");
+
+  triggerKey(38);
+
+  value += DEFAULT_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should increase negative values correctly");
+
+  triggerKey(40, "altKey");
+  triggerKey(40, "altKey");
+
+  value -= SLOW_VALUE_MULTIPLIER * 2;
+  is(widget.getValueAt(0), val(value),
+     "Should decrease float numbers correctly");
+
+  triggerKey(38, "altKey");
+
+  value += SLOW_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should increase float numbers correctly");
+
+  triggerKey = null;
+});
+
+// Triggers the specified keyCode and modifier key on
+// first filter's input
+function triggerKey(key, modifier) {
+  const filter = this.el.querySelector(".filters").children[0];
+  const input = filter.querySelector("input");
+
+  this._keyDown({
+    target: input,
+    keyCode: key,
+    [modifier]: true,
+    preventDefault: function() {}
+  });
+}
+
+function val(value) {
+  let v = value.toFixed(1);
+
+  if (v.indexOf(".0") > -1) {
+    v = v.slice(0, -2);
+  }
+  return `rgb(0, 0, 0) ${v}px 1px 0px`;
+}
diff --git a/browser/devtools/shared/test/browser_filter-editor-10.js b/browser/devtools/shared/test/browser_filter-editor-10.js
new file mode 100644
index 000000000000..2965ceea8304
--- /dev/null
+++ b/browser/devtools/shared/test/browser_filter-editor-10.js
@@ -0,0 +1,87 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+// Tests the Filter Editor Widget inputs increase/decrease value when cursor is
+// on a number using arrow keys if cursor is behind/mid/after the number strings
+
+const TEST_URI = "chrome://browser/content/devtools/filter-frame.xhtml";
+const {CSSFilterEditorWidget} = require("devtools/shared/widgets/FilterWidget");
+
+const FAST_VALUE_MULTIPLIER = 10;
+const SLOW_VALUE_MULTIPLIER = 0.1;
+const DEFAULT_VALUE_MULTIPLIER = 1;
+
+add_task(function*() {
+  yield promiseTab("about:blank");
+  let [host, win, doc] = yield createHost("bottom", TEST_URI);
+
+  const container = doc.querySelector("#container");
+  const initialValue = "drop-shadow(rgb(0, 0, 0) 10px 1px 0px)";
+  let widget = new CSSFilterEditorWidget(container, initialValue);
+  const input = widget.el.querySelector("input");
+
+  let value = 10;
+
+  triggerKey = triggerKey.bind(widget);
+
+  info("Test increment/decrement of string-type numbers without selection");
+
+  input.setSelectionRange(14, 14);
+  triggerKey(40);
+
+  value -= DEFAULT_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should work with cursor in the middle of number");
+
+  input.setSelectionRange(13, 13);
+  triggerKey(38);
+
+  value += DEFAULT_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should work with cursor before the number");
+
+  input.setSelectionRange(15, 15);
+  triggerKey(40);
+
+  value -= DEFAULT_VALUE_MULTIPLIER;
+  is(widget.getValueAt(0), val(value),
+     "Should work with cursor after the number");
+
+  info("Test increment/decrement of string-type numbers with a selection");
+
+  input.setSelectionRange(13, 15);
+  triggerKey(38);
+  input.setSelectionRange(13, 18);
+  triggerKey(38);
+
+  value += DEFAULT_VALUE_MULTIPLIER * 2;
+  is(widget.getValueAt(0), val(value),
+     "Should work if a there is a selection, starting with the number");
+
+  triggerKey = null;
+});
+
+// Triggers the specified keyCode and modifier key on
+// first filter's input
+function triggerKey(key, modifier) {
+  const filter = this.el.querySelector(".filters").children[0];
+  const input = filter.querySelector("input");
+
+  this._keyDown({
+    target: input,
+    keyCode: key,
+    [modifier]: true,
+    preventDefault: function() {}
+  });
+}
+
+function val(value) {
+  let v = value.toFixed(1);
+
+  if (v.indexOf(".0") > -1) {
+    v = v.slice(0, -2);
+  }
+  return `rgb(0, 0, 0) ${v}px 1px 0px`;
+}
diff --git a/browser/devtools/shared/widgets/FilterWidget.js b/browser/devtools/shared/widgets/FilterWidget.js
index 51c6a99d1f68..8d35d254be28 100644
--- a/browser/devtools/shared/widgets/FilterWidget.js
+++ b/browser/devtools/shared/widgets/FilterWidget.js
@@ -113,6 +113,7 @@ function CSSFilterEditorWidget(el, value = "") {
   this._mouseMove = this._mouseMove.bind(this);
   this._mouseUp = this._mouseUp.bind(this);
   this._mouseDown = this._mouseDown.bind(this);
+  this._keyDown = this._keyDown.bind(this);
   this._input = this._input.bind(this);
 
   this._initMarkup();
@@ -195,6 +196,7 @@ CSSFilterEditorWidget.prototype = {
     this.addButton.addEventListener("click", this._addButtonClick);
     this.list.addEventListener("click", this._removeButtonClick);
     this.list.addEventListener("mousedown", this._mouseDown);
+    this.list.addEventListener("keydown", this._keyDown);
 
     // These events are event delegators for
     // drag-drop re-ordering and label-dragging
@@ -205,9 +207,77 @@ CSSFilterEditorWidget.prototype = {
     this.list.addEventListener("input", this._input);
   },
 
+  _getFilterElementIndex: function(el) {
+    return [...this.list.children].indexOf(el);
+  },
+
+  _keyDown: function(e) {
+    if (e.target.tagName.toLowerCase() !== "input" ||
+       (e.keyCode !== 40 && e.keyCode !== 38)) {
+      return;
+    }
+    let input = e.target;
+
+    const direction = e.keyCode === 40 ? -1 : 1;
+
+    let multiplier = DEFAULT_VALUE_MULTIPLIER;
+    if (e.altKey) {
+      multiplier = SLOW_VALUE_MULTIPLIER;
+    } else if (e.shiftKey) {
+      multiplier = FAST_VALUE_MULTIPLIER;
+    }
+
+    const filterEl = e.target.closest(".filter");
+    const index = this._getFilterElementIndex(filterEl);
+    const filter = this.filters[index];
+
+    // Filters that have units are number-type filters. For them,
+    // the value can be incremented/decremented simply.
+    // For other types of filters (e.g. drop-shadow) we need to check
+    // if the keypress happened close to a number first.
+    if (filter.unit) {
+      let startValue = parseFloat(e.target.value);
+      let value = startValue + direction * multiplier;
+
+      const [min, max] = this._definition(filter.name).range;
+      value = value < min ? min :
+              value > max ? max : value;
+
+      input.value = fixFloat(value);
+
+      this.updateValueAt(index, value);
+    } else {
+      let selectionStart = input.selectionStart;
+      let num = getNeighbourNumber(input.value, selectionStart);
+      if (!num) {
+        return;
+      }
+
+      let {start, end, value} = num;
+
+      let split = input.value.split("");
+      let computed = fixFloat(value + direction * multiplier),
+          dotIndex = computed.indexOf(".0");
+      if (dotIndex > -1) {
+        computed = computed.slice(0, -2);
+
+        selectionStart = selectionStart > start + dotIndex ?
+                                          start + dotIndex :
+                                          selectionStart;
+      }
+      split.splice(start, end - start, computed);
+
+      value = split.join("");
+      input.value = value;
+      this.updateValueAt(index, value);
+      input.setSelectionRange(selectionStart, selectionStart);
+    }
+    e.preventDefault();
+  },
+
   _input: function(e) {
     let filterEl = e.target.closest(".filter"),
-        index = [...this.list.children].indexOf(filterEl),
+        index = this._getFilterElementIndex(filterEl),
         filter = this.filters[index],
         def = this._definition(filter.name);
 
@@ -231,7 +301,7 @@ CSSFilterEditorWidget.prototype = {
     } else if (e.target.classList.contains("devtools-draglabel")) {
       let label = e.target,
           input = filterEl.querySelector("input"),
-          index = [...this.list.children].indexOf(filterEl);
+          index = this._getFilterElementIndex(filterEl);
 
       this._dragging = {
         index, label, input,
@@ -273,7 +343,7 @@ CSSFilterEditorWidget.prototype = {
     }
 
     let filterEl = e.target.closest(".filter");
-    let index = [...this.list.children].indexOf(filterEl);
+    let index = this._getFilterElementIndex(filterEl);
     this.removeAt(index);
   },
 
@@ -622,6 +692,7 @@ CSSFilterEditorWidget.prototype = {
     this.addButton.removeEventListener("click", this._addButtonClick);
     this.list.removeEventListener("click", this._removeButtonClick);
     this.list.removeEventListener("mousedown", this._mouseDown);
+    this.list.removeEventListener("keydown", this._keyDown);
 
     // These events are used for drag drop re-ordering
     this.win.removeEventListener("mousemove", this._mouseMove);
@@ -718,3 +789,40 @@ function tokenizeComputedFilter(css) {
 
   return filters;
 }
+
+/**
+  * Finds neighbour number characters of an index in a string
+  * the numbers may be floats (containing dots)
+  * It's assumed that the value given to this function is a valid number
+  *
+  * @param {String} string
+  *        The string containing numbers
+  * @param {Number} index
+  *        The index to look for neighbours for
+  * @return {Object}
+  *         returns null if no number is found
+  *         value: The number found
+  *         start: The number's starting index
+  *         end: The number's ending index
+  */
+function getNeighbourNumber(string, index) {
+  if (!/\d/.test(string)) {
+    return null;
+  }
+
+  let left = /-?[0-9.]*$/.exec(string.slice(0, index)),
+      right = /-?[0-9.]*/.exec(string.slice(index));
+
+  left = left ? left[0] : "";
+  right = right ? right[0] : "";
+
+  if (!right && !left) {
+    return null;
+  }
+
+  return {
+    value: fixFloat(left + right, true),
+    start: index - left.length,
+    end: index + right.length
+  };
+}