diff --git a/browser/themes/shared/tabs.css b/browser/themes/shared/tabs.css
index 3a131204678b..ce68cde3321e 100644
--- a/browser/themes/shared/tabs.css
+++ b/browser/themes/shared/tabs.css
@@ -452,14 +452,15 @@
   margin-inline-end: calc(var(--inline-tab-padding) / -2);
   width: 24px;
   height: 24px;
-  padding: 7px;
+  padding: 6px;
   border-radius: var(--tab-border-radius);
+  list-style-image: url(chrome://global/skin/icons/close-12.svg);
 }
 
 /* The following rulesets allow showing more of the tab title */
 .tabbrowser-tab:not([labelendaligned],:hover) > .tab-stack > .tab-content > .tab-close-button {
   padding-inline-start: 0;
-  width: 17px;
+  width: 18px;
 }
 
 .tabbrowser-tab[visuallyselected=true]:not([labelendaligned]):hover,
diff --git a/toolkit/content/widgets/message-bar.css b/toolkit/content/widgets/message-bar.css
index 0de6d5a9e605..56cb012730ce 100644
--- a/toolkit/content/widgets/message-bar.css
+++ b/toolkit/content/widgets/message-bar.css
@@ -7,9 +7,9 @@
   --warn-icon-url: url("chrome://global/skin/icons/warning.svg");
   --success-icon-url: url("chrome://global/skin/icons/check.svg");
   --error-icon-url: url("chrome://global/skin/icons/error.svg");
-  --close-icon-url: url("chrome://global/skin/icons/close.svg");
+  --close-icon-url: url("chrome://global/skin/icons/close-12.svg");
   --icon-size: 16px;
-  --close-icon-size: 32px;
+  --close-icon-size: 24px;
 }
 
 :host([message-bar-type=infobar]) {
@@ -226,7 +226,7 @@
 
 .close {
   margin: 4px 8px;
-  background-size: 16px;
+  background-size: 12px;
 }
 
 .notification-button {
diff --git a/toolkit/themes/shared/desktop-jar.inc.mn b/toolkit/themes/shared/desktop-jar.inc.mn
index d752cae13dc6..c2e92a57db33 100644
--- a/toolkit/themes/shared/desktop-jar.inc.mn
+++ b/toolkit/themes/shared/desktop-jar.inc.mn
@@ -62,6 +62,7 @@
   skin/classic/global/icons/check-partial.svg              (../../shared/icons/check-partial.svg)
   skin/classic/global/icons/chevron.svg                    (../../shared/icons/chevron.svg)
   skin/classic/global/icons/close.svg                      (../../shared/icons/close.svg)
+  skin/classic/global/icons/close-12.svg                   (../../shared/icons/close-12.svg)
   skin/classic/global/icons/close-fill.svg                 (../../shared/icons/close-fill.svg)
   skin/classic/global/icons/columnpicker.svg               (../../shared/icons/columnpicker.svg)
   skin/classic/global/icons/defaultFavicon.svg             (../../shared/icons/defaultFavicon.svg)
diff --git a/toolkit/themes/shared/icons/close-12.svg b/toolkit/themes/shared/icons/close-12.svg
new file mode 100644
index 000000000000..9df6bee3b610
--- /dev/null
+++ b/toolkit/themes/shared/icons/close-12.svg
@@ -0,0 +1,6 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 12 12" width="12" height="12" fill="context-fill" fill-opacity="context-fill-opacity">
+  <path d="M5.859 6.849 2.854 9.854a.5.5 0 0 1-.707-.707l3.005-3.005 0-.283-3.005-3.006a.5.5 0 0 1 .707-.707l3.005 3.005.283 0 3.005-3.005a.5.5 0 0 1 .707.707L6.849 5.859l0 .283 3.005 3.005a.5.5 0 0 1-.707.707L6.142 6.849l.001.001-.284-.001z"/>
+</svg>