diff --git a/.changeset/poor-wasps-stare.md b/.changeset/poor-wasps-stare.md
new file mode 100644
index 00000000000..deca619ad6a
--- /dev/null
+++ b/.changeset/poor-wasps-stare.md
@@ -0,0 +1,7 @@
+---
+"@primer/react": patch
+---
+
+Use IconButton instead of ButtonClose in v1 Dialog.
+
+<!-- Changed components: Dialog -->
diff --git a/src/Dialog.tsx b/src/Dialog.tsx
index 2df90952959..2487bc2fe34 100644
--- a/src/Dialog.tsx
+++ b/src/Dialog.tsx
@@ -1,6 +1,6 @@
 import React, {forwardRef, useRef} from 'react'
 import styled from 'styled-components'
-import ButtonClose from './deprecated/Button/ButtonClose'
+import {IconButton} from './Button'
 import {get} from './constants'
 import Box from './Box'
 import useDialog from './hooks/useDialog'
@@ -8,6 +8,7 @@ import sx, {SxProp} from './sx'
 import Text from './Text'
 import {ComponentProps} from './utils/types'
 import {useRefObjectAsForwardedRef} from './hooks/useRefObjectAsForwardedRef'
+import {XIcon} from '@primer/octicons-react'
 
 const noop = () => null
 
@@ -119,10 +120,13 @@ const Dialog = forwardRef<HTMLDivElement, InternalDialogProps>(
       <>
         <Overlay ref={overlayRef} />
         <DialogBase tabIndex={-1} ref={modalRef} role="dialog" aria-modal="true" {...props} {...getDialogProps()}>
-          <ButtonClose
+          <IconButton
+            icon={XIcon}
             ref={closeButtonRef}
             onClick={onCloseClick}
-            sx={{position: 'absolute', top: '16px', right: '16px'}}
+            sx={{position: 'absolute', top: '8px', right: '16px'}}
+            aria-label="Close"
+            variant="invisible"
           />
           {children}
         </DialogBase>
diff --git a/src/__tests__/__snapshots__/Dialog.test.tsx.snap b/src/__tests__/__snapshots__/Dialog.test.tsx.snap
index c2b293951fa..ef2c3f65c76 100644
--- a/src/__tests__/__snapshots__/Dialog.test.tsx.snap
+++ b/src/__tests__/__snapshots__/Dialog.test.tsx.snap
@@ -61,35 +61,243 @@ exports[`Dialog renders consistently 1`] = `
   padding: 16px;
 }
 
-.c3 {
+.c1 {
+  border-radius: 6px;
+  border: 1px solid;
+  border-color: transparent;
+  font-family: inherit;
+  font-weight: 500;
   font-size: 14px;
-  font-weight: 600;
-  font-family: sans-serif;
-  color: #1F2328;
+  cursor: pointer;
+  -webkit-appearance: none;
+  -moz-appearance: none;
+  appearance: none;
+  -webkit-user-select: none;
+  -moz-user-select: none;
+  -ms-user-select: none;
+  user-select: none;
+  -webkit-text-decoration: none;
+  text-decoration: none;
+  text-align: center;
+  display: -webkit-box;
+  display: -webkit-flex;
+  display: -ms-flexbox;
+  display: flex;
+  -webkit-align-items: center;
+  -webkit-box-align: center;
+  -ms-flex-align: center;
+  align-items: center;
+  -webkit-box-pack: justify;
+  -webkit-justify-content: space-between;
+  -ms-flex-pack: justify;
+  justify-content: space-between;
+  height: 32px;
+  padding: 0 12px;
+  gap: 8px;
+  min-width: -webkit-max-content;
+  min-width: -moz-max-content;
+  min-width: max-content;
+  -webkit-transition: 80ms cubic-bezier(0.65,0,0.35,1);
+  transition: 80ms cubic-bezier(0.65,0,0.35,1);
+  -webkit-transition-property: color,fill,background-color,border-color;
+  transition-property: color,fill,background-color,border-color;
+  color: #24292f;
+  background-color: transparent;
+  box-shadow: none;
 }
 
-.c5 {
-  font-family: sans-serif;
+.c1:focus:not(:disabled) {
+  box-shadow: none;
+  outline: 2px solid #0969da;
+  outline-offset: -2px;
 }
 
-.c1 {
-  border: none;
-  padding: 0;
-  background: transparent;
-  cursor: pointer;
-  border-radius: 6px;
+.c1:focus:not(:disabled):not(:focus-visible) {
+  outline: solid 1px transparent;
+}
+
+.c1:focus-visible:not(:disabled) {
+  box-shadow: none;
+  outline: 2px solid #0969da;
+  outline-offset: -2px;
+}
+
+.c1[href] {
+  display: -webkit-inline-box;
+  display: -webkit-inline-flex;
+  display: -ms-inline-flexbox;
+  display: inline-flex;
+}
+
+.c1[href]:hover {
+  -webkit-text-decoration: none;
+  text-decoration: none;
+}
+
+.c1:hover {
+  -webkit-transition-duration: 80ms;
+  transition-duration: 80ms;
+}
+
+.c1:active {
+  -webkit-transition: none;
+  transition: none;
+}
+
+.c1:disabled {
+  cursor: not-allowed;
+  box-shadow: none;
+  color: #8c959f;
+}
+
+.c1:disabled [data-component=ButtonCounter],
+.c1:disabled [data-component="leadingVisual"],
+.c1:disabled [data-component="trailingAction"] {
+  color: inherit;
+}
+
+.c1 [data-component=ButtonCounter] {
+  font-size: 14px;
+}
+
+.c1[data-component=IconButton] {
+  display: inline-grid;
+  padding: unset;
+  place-content: center;
+  width: 32px;
+  min-width: unset;
+}
+
+.c1[data-size="small"] {
+  padding: 0 8px;
+  height: 28px;
+  gap: 4px;
+  font-size: 12px;
+}
+
+.c1[data-size="small"] [data-component="text"] {
+  line-height: calc(20 / 12);
+}
+
+.c1[data-size="small"] [data-component=ButtonCounter] {
+  font-size: 12px;
+}
+
+.c1[data-size="small"] [data-component="buttonContent"] > :not(:last-child) {
+  margin-right: 4px;
+}
+
+.c1[data-size="small"][data-component=IconButton] {
+  width: 28px;
+  padding: unset;
+}
+
+.c1[data-size="large"] {
+  padding: 0 16px;
+  height: 40px;
+  gap: 8px;
+}
+
+.c1[data-size="large"] [data-component="buttonContent"] > :not(:last-child) {
+  margin-right: 8px;
+}
+
+.c1[data-size="large"][data-component=IconButton] {
+  width: 40px;
+  padding: unset;
+}
+
+.c1[data-block="block"] {
+  width: 100%;
+}
+
+.c1 [data-component="leadingVisual"] {
+  grid-area: leadingVisual;
+  color: #656d76;
+}
+
+.c1 [data-component="text"] {
+  grid-area: text;
+  line-height: calc(20/14);
+  white-space: nowrap;
+}
+
+.c1 [data-component="trailingVisual"] {
+  grid-area: trailingVisual;
+}
+
+.c1 [data-component="trailingAction"] {
+  margin-right: -4px;
+  color: #656d76;
+}
+
+.c1 [data-component="buttonContent"] {
+  -webkit-flex: 1 0 auto;
+  -ms-flex: 1 0 auto;
+  flex: 1 0 auto;
+  display: grid;
+  grid-template-areas: "leadingVisual text trailingVisual";
+  grid-template-columns: min-content minmax(0,auto) min-content;
+  -webkit-align-items: center;
+  -webkit-box-align: center;
+  -ms-flex-align: center;
+  align-items: center;
+  -webkit-align-content: center;
+  -ms-flex-line-pack: center;
+  align-content: center;
+}
+
+.c1 [data-component="buttonContent"] > :not(:last-child) {
+  margin-right: 8px;
+}
+
+.c1:hover:not([disabled]) {
+  background-color: rgba(208,215,222,0.32);
+}
+
+.c1:active:not([disabled]) {
+  background-color: rgba(208,215,222,0.48);
+}
+
+.c1[aria-expanded=true] {
+  background-color: rgba(208,215,222,0.24);
+}
+
+.c1[data-component="IconButton"][data-no-visuals] {
   color: #656d76;
+}
+
+.c1[data-no-visuals] {
+  color: #0969da;
+}
+
+.c1:has([data-component="ButtonCounter"]) {
+  color: #24292f;
+}
+
+.c1:disabled[data-no-visuals] {
+  color: #8c959f;
+}
+
+.c1:disabled[data-no-visuals] [data-component=ButtonCounter] {
+  color: inherit;
+}
+
+.c1[data-no-visuals="true"] {
   position: absolute;
-  top: 16px;
+  top: 8px;
   right: 16px;
 }
 
-.c1:focus {
-  outline: solid 2px #0969da;
+.c3 {
+  font-size: 14px;
+  font-weight: 600;
+  font-family: sans-serif;
+  color: #1F2328;
 }
 
-.c1:hover {
-  color: #0969da;
+.c5 {
+  font-family: sans-serif;
 }
 
 .c0 {
@@ -120,6 +328,12 @@ exports[`Dialog renders consistently 1`] = `
   display: flex;
 }
 
+@media (forced-colors:active) {
+  .c1:focus {
+    outline: solid 1px transparent;
+  }
+}
+
 @media screen and (max-width:750px) {
   .c0 {
     width: 100vw;
@@ -146,6 +360,9 @@ exports[`Dialog renders consistently 1`] = `
     <button
       aria-label="Close"
       className="c1"
+      data-block={null}
+      data-component="IconButton"
+      data-no-visuals={true}
       onClick={[Function]}
     >
       <svg