diff --git a/lib/commons/text/is-icon-ligature.js b/lib/commons/text/is-icon-ligature.js
index 7924b0bbc9..428117f0de 100644
--- a/lib/commons/text/is-icon-ligature.js
+++ b/lib/commons/text/is-icon-ligature.js
@@ -93,11 +93,7 @@ export default function isIconLigature(
 
   // keep track of each font encountered and the number of times it shows up
   // as a ligature.
-  if (!cache.get('fonts')) {
-    cache.set('fonts', {});
-  }
-  const fonts = cache.get('fonts');
-
+  const fonts = cache.get('fonts', () => ({}));
   const style = window.getComputedStyle(textVNode.parent.actualNode);
   const fontFamily = style.getPropertyValue('font-family');
 
@@ -109,7 +105,7 @@ export default function isIconLigature(
   }
   const font = fonts[fontFamily];
 
-  // improve the performance by only comparing the image data of a fon a certain number of times
+  // improve the performance by only comparing the image data of a font a certain number of times
   // NOTE: This MIGHT cause an issue if someone uses an icon font to render actual text.
   //   We're leaving this as-is, unless someone reports a false positive over it.
   if (font.occurrences >= occurrenceThreshold) {
@@ -143,6 +139,14 @@ export default function isIconLigature(
   const firstChar = nodeValue.charAt(0);
   let width = canvasContext.measureText(firstChar).width;
 
+  // we already checked for typical zero-width unicode formatting characters further up,
+  // so we assume that any remaining zero-width characters are part of an icon ligature
+  // @see https://github.com/dequelabs/axe-core/issues/3918
+  if (width === 0) {
+    font.numLigatures++;
+    return true;
+  }
+
   // ensure font meets the 30px width requirement (30px font-size doesn't
   // necessarily mean its 30px wide when drawn)
   if (width < 30) {
diff --git a/test/assets/ZeroWidth0Char.woff b/test/assets/ZeroWidth0Char.woff
new file mode 100644
index 0000000000..3c26a6e1ed
Binary files /dev/null and b/test/assets/ZeroWidth0Char.woff differ
diff --git a/test/commons/text/is-icon-ligature.js b/test/commons/text/is-icon-ligature.js
index ee11e2b8eb..2da2ba8ba2 100644
--- a/test/commons/text/is-icon-ligature.js
+++ b/test/commons/text/is-icon-ligature.js
@@ -1,67 +1,73 @@
-describe('text.isIconLigature', function () {
+describe('text.isIconLigature', () => {
   'use strict';
 
-  var isIconLigature = axe.commons.text.isIconLigature;
-  var queryFixture = axe.testUtils.queryFixture;
-  var fontApiSupport = !!document.fonts;
+  const isIconLigature = axe.commons.text.isIconLigature;
+  const queryFixture = axe.testUtils.queryFixture;
+  const fontApiSupport = !!document.fonts;
 
-  before(function (done) {
+  before(done => {
     if (!fontApiSupport) {
       done();
     }
 
-    var firaFont = new FontFace(
+    const firaFont = new FontFace(
       'Fira Code',
       'url(/test/assets/FiraCode-Regular.woff)'
     );
-    var ligatureFont = new FontFace(
+    const ligatureFont = new FontFace(
       'LigatureSymbols',
       'url(/test/assets/LigatureSymbols.woff)'
     );
-    var materialFont = new FontFace(
+    const materialFont = new FontFace(
       'Material Icons',
       'url(/test/assets/MaterialIcons.woff2)'
     );
-    var robotoFont = new FontFace('Roboto', 'url(/test/assets/Roboto.woff2)');
+    const robotoFont = new FontFace('Roboto', 'url(/test/assets/Roboto.woff2)');
+    const zeroWidth0CharFont = new FontFace(
+      'ZeroWidth0Char',
+      'url(/test/assets/ZeroWidth0Char.woff)'
+    );
 
     window.Promise.all([
       firaFont.load(),
       ligatureFont.load(),
       materialFont.load(),
-      robotoFont.load()
-    ]).then(function () {
+      robotoFont.load(),
+      zeroWidth0CharFont.load()
+    ]).then(() => {
       document.fonts.add(firaFont);
       document.fonts.add(ligatureFont);
       document.fonts.add(materialFont);
       document.fonts.add(robotoFont);
+      document.fonts.add(zeroWidth0CharFont);
       done();
     });
   });
 
-  it('should return false for normal text', function () {
-    var target = queryFixture('<div id="target">Normal text</div>');
+  it('should return false for normal text', () => {
+    const target = queryFixture('<div id="target">Normal text</div>');
     assert.isFalse(isIconLigature(target.children[0]));
   });
 
-  it('should return false for emoji', function () {
-    var target = queryFixture('<div id="target">🌎</div>');
+  it('should return false for emoji', () => {
+    const target = queryFixture('<div id="target">🌎</div>');
     assert.isFalse(isIconLigature(target.children[0]));
   });
 
-  it('should return false for non-bmp unicode', function () {
-    var target = queryFixture('<div id="target">◓</div>');
+  it('should return false for non-bmp unicode', () => {
+    const target = queryFixture('<div id="target">◓</div>');
     assert.isFalse(isIconLigature(target.children[0]));
   });
 
-  it('should return false for whitespace strings', function () {
-    var target = queryFixture('<div id="target">     </div>');
+  it('should return false for whitespace strings', () => {
+    const target = queryFixture('<div id="target">     </div>');
     assert.isFalse(isIconLigature(target.children[0]));
   });
 
   (fontApiSupport ? it : it.skip)(
     'should return false for common ligatures (fi)',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: Roboto">figure</div>'
       );
       assert.isFalse(isIconLigature(target.children[0]));
@@ -70,8 +76,8 @@ describe('text.isIconLigature', function () {
 
   (fontApiSupport ? it : it.skip)(
     'should return false for common ligatures (ff)',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: Roboto">ffugative</div>'
       );
       assert.isFalse(isIconLigature(target.children[0]));
@@ -80,8 +86,8 @@ describe('text.isIconLigature', function () {
 
   (fontApiSupport ? it : it.skip)(
     'should return false for common ligatures (fl)',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: Roboto">flu shot</div>'
       );
       assert.isFalse(isIconLigature(target.children[0]));
@@ -90,8 +96,8 @@ describe('text.isIconLigature', function () {
 
   (fontApiSupport ? it : it.skip)(
     'should return false for common ligatures (ffi)',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: Roboto">ffigure</div>'
       );
       assert.isFalse(isIconLigature(target.children[0]));
@@ -100,8 +106,8 @@ describe('text.isIconLigature', function () {
 
   (fontApiSupport ? it : it.skip)(
     'should return false for common ligatures (ffl)',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: Roboto">fflu shot</div>'
       );
       assert.isFalse(isIconLigature(target.children[0]));
@@ -110,16 +116,16 @@ describe('text.isIconLigature', function () {
 
   (fontApiSupport ? it : it.skip)(
     'should return true for an icon ligature',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: \'Material Icons\'">delete</div>'
       );
       assert.isTrue(isIconLigature(target.children[0]));
     }
   );
 
-  (fontApiSupport ? it : it.skip)('should trim the string', function () {
-    var target = queryFixture(
+  (fontApiSupport ? it : it.skip)('should trim the string', () => {
+    const target = queryFixture(
       '<div id="target" style="font-family: Roboto">  fflu shot  </div>'
     );
     assert.isFalse(isIconLigature(target.children[0]));
@@ -127,18 +133,28 @@ describe('text.isIconLigature', function () {
 
   (fontApiSupport ? it : it.skip)(
     'should return true for a font that has no character data',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: \'Material Icons\'">f</div>'
       );
       assert.isTrue(isIconLigature(target.children[0]));
     }
   );
 
+  (fontApiSupport ? it : it.skip)(
+    'should return true for a font that has zero width characters',
+    () => {
+      const target = queryFixture(
+        '<div id="target" style="font-family: \'ZeroWidth0Char\'">0</div>'
+      );
+      assert.isTrue(isIconLigature(target.children[0]));
+    }
+  );
+
   (fontApiSupport ? it : it.skip)(
     'should return false for a programming text ligature',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: Fira Code">!==</div>'
       );
       assert.isFalse(isIconLigature(target.children[0]));
@@ -147,8 +163,8 @@ describe('text.isIconLigature', function () {
 
   (fontApiSupport ? it : it.skip)(
     'should return true for an icon ligature with low pixel difference',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: \'Material Icons\'">keyboard_arrow_left</div>'
       );
       assert.isTrue(isIconLigature(target.children[0]));
@@ -157,8 +173,8 @@ describe('text.isIconLigature', function () {
 
   (fontApiSupport ? it : it.skip)(
     'should return true after the 3rd time the font is an icon',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: \'LigatureSymbols\'">delete</div>'
       );
 
@@ -174,8 +190,8 @@ describe('text.isIconLigature', function () {
 
   (fontApiSupport ? it : it.skip)(
     'should return false after the 3rd time the font is not an icon',
-    function () {
-      var target = queryFixture(
+    () => {
+      const target = queryFixture(
         '<div id="target" style="font-family: \'Roboto\'">__non-icon text__</div>'
       );
 
@@ -189,11 +205,11 @@ describe('text.isIconLigature', function () {
     }
   );
 
-  describe('pixelThreshold', function () {
+  describe('pixelThreshold', () => {
     (fontApiSupport ? it : it.skip)(
       'should allow higher percent (will not flag icon ligatures)',
-      function () {
-        var target = queryFixture(
+      () => {
+        const target = queryFixture(
           '<div id="target" style="font-family: \'LigatureSymbols\'">delete</div>'
         );
 
@@ -204,8 +220,8 @@ describe('text.isIconLigature', function () {
 
     (fontApiSupport ? it : it.skip)(
       'should allow lower percent (will flag text ligatures)',
-      function () {
-        var target = queryFixture(
+      () => {
+        const target = queryFixture(
           '<div id="target" style="font-family: Roboto">figure</div>'
         );
         assert.isTrue(isIconLigature(target.children[0], 0));
@@ -213,11 +229,11 @@ describe('text.isIconLigature', function () {
     );
   });
 
-  describe('occurrenceThreshold', function () {
+  describe('occurrenceThreshold', () => {
     (fontApiSupport ? it : it.skip)(
       'should change the number of times a font is seen before returning',
-      function () {
-        var target = queryFixture(
+      () => {
+        const target = queryFixture(
           '<div id="target" style="font-family: \'LigatureSymbols\'">delete</div>'
         );