diff --git a/docs/pages/api-docs/list-item-icon.json b/docs/pages/api-docs/list-item-icon.json
index a0c1d355e79fa6..dac9ee8aba40dd 100644
--- a/docs/pages/api-docs/list-item-icon.json
+++ b/docs/pages/api-docs/list-item-icon.json
@@ -1,7 +1,8 @@
 {
   "props": {
     "children": { "type": { "name": "node" } },
-    "classes": { "type": { "name": "object" } }
+    "classes": { "type": { "name": "object" } },
+    "sx": { "type": { "name": "object" } }
   },
   "name": "ListItemIcon",
   "styles": {
@@ -14,6 +15,6 @@
   "filename": "/packages/material-ui/src/ListItemIcon/ListItemIcon.js",
   "inheritance": null,
   "demos": "<ul><li><a href=\"/components/lists/\">Lists</a></li></ul>",
-  "styledComponent": false,
+  "styledComponent": true,
   "cssComponent": false
 }
diff --git a/docs/translations/api-docs/list-item-icon/list-item-icon.json b/docs/translations/api-docs/list-item-icon/list-item-icon.json
index 9c1ef7a1b4f281..400c88d2d77e1a 100644
--- a/docs/translations/api-docs/list-item-icon/list-item-icon.json
+++ b/docs/translations/api-docs/list-item-icon/list-item-icon.json
@@ -2,7 +2,8 @@
   "componentDescription": "A simple wrapper to apply `List` styles to an `Icon` or `SvgIcon`.",
   "propDescriptions": {
     "children": "The content of the component, normally <code>Icon</code>, <code>SvgIcon</code>, or a <code>@material-ui/icons</code> SVG icon element.",
-    "classes": "Override or extend the styles applied to the component. See <a href=\"#css\">CSS API</a> below for more details."
+    "classes": "Override or extend the styles applied to the component. See <a href=\"#css\">CSS API</a> below for more details.",
+    "sx": "The system prop that allows defining system overrides as well as additional CSS styles. See the <a href=\"/system/basics/#the-sx-prop\">`sx` page</a> for more details."
   },
   "classDescriptions": {
     "root": { "description": "Styles applied to the root element." },
diff --git a/packages/material-ui/src/ListItemIcon/ListItemIcon.d.ts b/packages/material-ui/src/ListItemIcon/ListItemIcon.d.ts
index 80de403db229e2..23602c6a8228c0 100644
--- a/packages/material-ui/src/ListItemIcon/ListItemIcon.d.ts
+++ b/packages/material-ui/src/ListItemIcon/ListItemIcon.d.ts
@@ -1,4 +1,5 @@
-import { InternalStandardProps as StandardProps } from '..';
+import { SxProps } from '@material-ui/system';
+import { InternalStandardProps as StandardProps, Theme } from '..';
 
 export interface ListItemIconProps extends StandardProps<React.HTMLAttributes<HTMLDivElement>> {
   /**
@@ -15,6 +16,10 @@ export interface ListItemIconProps extends StandardProps<React.HTMLAttributes<HT
     /** Styles applied to the root element when the parent `ListItem` uses `alignItems="flex-start"`. */
     alignItemsFlexStart?: string;
   };
+  /**
+   * The system prop that allows defining system overrides as well as additional CSS styles.
+   */
+  sx?: SxProps<Theme>;
 }
 
 export type ListItemIconClassKey = keyof NonNullable<ListItemIconProps['classes']>;
diff --git a/packages/material-ui/src/ListItemIcon/ListItemIcon.js b/packages/material-ui/src/ListItemIcon/ListItemIcon.js
index 381da79d92ecd2..8aa3376010b569 100644
--- a/packages/material-ui/src/ListItemIcon/ListItemIcon.js
+++ b/packages/material-ui/src/ListItemIcon/ListItemIcon.js
@@ -1,39 +1,69 @@
 import * as React from 'react';
 import PropTypes from 'prop-types';
 import clsx from 'clsx';
-import withStyles from '../styles/withStyles';
+import { deepmerge } from '@material-ui/utils';
+import { unstable_composeClasses as composeClasses } from '@material-ui/unstyled';
+import experimentalStyled from '../styles/experimentalStyled';
+import useThemeProps from '../styles/useThemeProps';
+import { getListItemIconUtilityClass } from './listItemIconClasses';
 import ListContext from '../List/ListContext';
 
-export const styles = (theme) => ({
-  /* Styles applied to the root element. */
-  root: {
-    minWidth: 56,
-    color: theme.palette.action.active,
-    flexShrink: 0,
-    display: 'inline-flex',
+const overridesResolver = (props, styles) => {
+  const { styleProps } = props;
+
+  return deepmerge(styles.root || {}, {
+    ...(styleProps.alignItems === 'flex-start' && styles.alignItemsFlexStart),
+  });
+};
+
+const useUtilityClasses = (styleProps) => {
+  const { alignItems, classes } = styleProps;
+
+  const slots = {
+    root: ['root', alignItems === 'flex-start' && 'alignItemsFlexStart'],
+  };
+
+  return composeClasses(slots, getListItemIconUtilityClass, classes);
+};
+
+const ListItemIconRoot = experimentalStyled(
+  'div',
+  {},
+  {
+    name: 'MuiListItemIcon',
+    slot: 'Root',
+    overridesResolver,
   },
+)(({ theme, styleProps }) => ({
+  /* Styles applied to the root element. */
+  minWidth: 56,
+  color: theme.palette.action.active,
+  flexShrink: 0,
+  display: 'inline-flex',
   /* Styles applied to the root element when the parent `ListItem` uses `alignItems="flex-start"`. */
-  alignItemsFlexStart: {
+  ...(styleProps.alignItems === 'flex-start' && {
     marginTop: 8,
-  },
-});
+  }),
+}));
 
 /**
  * A simple wrapper to apply `List` styles to an `Icon` or `SvgIcon`.
  */
-const ListItemIcon = React.forwardRef(function ListItemIcon(props, ref) {
-  const { classes, className, ...other } = props;
+const ListItemIcon = React.forwardRef(function ListItemIcon(inProps, ref) {
+  const props = useThemeProps({
+    props: inProps,
+    name: 'MuiListItemIcon',
+  });
+
+  const { className, ...other } = props;
   const context = React.useContext(ListContext);
+  const styleProps = { ...props, alignItems: context.alignItems };
+  const classes = useUtilityClasses(styleProps);
 
   return (
-    <div
-      className={clsx(
-        classes.root,
-        {
-          [classes.alignItemsFlexStart]: context.alignItems === 'flex-start',
-        },
-        className,
-      )}
+    <ListItemIconRoot
+      className={clsx(classes.root, className)}
+      styleProps={styleProps}
       ref={ref}
       {...other}
     />
@@ -58,6 +88,10 @@ ListItemIcon.propTypes = {
    * @ignore
    */
   className: PropTypes.string,
+  /**
+   * The system prop that allows defining system overrides as well as additional CSS styles.
+   */
+  sx: PropTypes.object,
 };
 
-export default withStyles(styles, { name: 'MuiListItemIcon' })(ListItemIcon);
+export default ListItemIcon;
diff --git a/packages/material-ui/src/ListItemIcon/ListItemIcon.test.js b/packages/material-ui/src/ListItemIcon/ListItemIcon.test.js
index 1d9fba71d27c4c..c50852b8eb4024 100644
--- a/packages/material-ui/src/ListItemIcon/ListItemIcon.test.js
+++ b/packages/material-ui/src/ListItemIcon/ListItemIcon.test.js
@@ -1,20 +1,12 @@
 import * as React from 'react';
-import { getClasses, createMount, describeConformance } from 'test/utils';
+import { createMount, describeConformanceV5 } from 'test/utils';
 import ListItemIcon from './ListItemIcon';
+import classes from './listItemIconClasses';
 
 describe('<ListItemIcon />', () => {
   const mount = createMount();
-  let classes;
 
-  before(() => {
-    classes = getClasses(
-      <ListItemIcon>
-        <span />
-      </ListItemIcon>,
-    );
-  });
-
-  describeConformance(
+  describeConformanceV5(
     <ListItemIcon>
       <div />
     </ListItemIcon>,
@@ -22,8 +14,9 @@ describe('<ListItemIcon />', () => {
       classes,
       inheritComponent: 'div',
       mount,
+      muiName: 'MuiListItemIcon',
       refInstanceof: window.HTMLDivElement,
-      skip: ['componentProp'],
+      skip: ['componentProp', 'componentsProp', 'themeVariants'],
     }),
   );
 });
diff --git a/packages/material-ui/src/ListItemIcon/index.d.ts b/packages/material-ui/src/ListItemIcon/index.d.ts
index 0adcbd950b46ea..befa5c4b06fce5 100644
--- a/packages/material-ui/src/ListItemIcon/index.d.ts
+++ b/packages/material-ui/src/ListItemIcon/index.d.ts
@@ -1,2 +1,4 @@
 export { default } from './ListItemIcon';
 export * from './ListItemIcon';
+export { default as listItemIconClasses } from './listItemIconClasses';
+export * from './listItemIconClasses';
diff --git a/packages/material-ui/src/ListItemIcon/index.js b/packages/material-ui/src/ListItemIcon/index.js
index 0bcbf23ba29322..01174ef3d39b49 100644
--- a/packages/material-ui/src/ListItemIcon/index.js
+++ b/packages/material-ui/src/ListItemIcon/index.js
@@ -1 +1,3 @@
 export { default } from './ListItemIcon';
+export { default as listItemIconClasses } from './listItemIconClasses';
+export * from './listItemIconClasses';
diff --git a/packages/material-ui/src/ListItemIcon/listItemIconClasses.d.ts b/packages/material-ui/src/ListItemIcon/listItemIconClasses.d.ts
new file mode 100644
index 00000000000000..7e6f52417590f5
--- /dev/null
+++ b/packages/material-ui/src/ListItemIcon/listItemIconClasses.d.ts
@@ -0,0 +1,10 @@
+export interface ListItemIconClasses {
+  root: string;
+  alignItemsFlexStart: string;
+}
+
+declare const listItemIconClasses: ListItemIconClasses;
+
+export function getListItemIconUtilityClass(slot: string): string;
+
+export default listItemIconClasses;
diff --git a/packages/material-ui/src/ListItemIcon/listItemIconClasses.js b/packages/material-ui/src/ListItemIcon/listItemIconClasses.js
new file mode 100644
index 00000000000000..973b8a0403d741
--- /dev/null
+++ b/packages/material-ui/src/ListItemIcon/listItemIconClasses.js
@@ -0,0 +1,12 @@
+import { generateUtilityClass, generateUtilityClasses } from '@material-ui/unstyled';
+
+export function getListItemIconUtilityClass(slot) {
+  return generateUtilityClass('MuiListItemIcon', slot);
+}
+
+const listItemIconClasses = generateUtilityClasses('MuiListItemIcon', [
+  'root',
+  'alignItemsFlexStart',
+]);
+
+export default listItemIconClasses;