diff --git a/app/soapbox/actions/admin.ts b/app/soapbox/actions/admin.ts
index e486ca873..ee4fae92c 100644
--- a/app/soapbox/actions/admin.ts
+++ b/app/soapbox/actions/admin.ts
@@ -1,5 +1,6 @@
 import { fetchRelationships } from 'soapbox/actions/accounts';
 import { importFetchedAccount, importFetchedAccounts, importFetchedStatuses } from 'soapbox/actions/importer';
+import { filterBadges, getTagDiff } from 'soapbox/utils/badges';
 import { getFeatures } from 'soapbox/utils/features';
 
 import api, { getLinks } from '../api';
@@ -413,6 +414,26 @@ const untagUsers = (accountIds: string[], tags: string[]) =>
       });
   };
 
+/** Synchronizes user tags to the backend. */
+const setTags = (accountId: string, oldTags: string[], newTags: string[]) =>
+  (dispatch: AppDispatch) => {
+    const diff = getTagDiff(oldTags, newTags);
+
+    return Promise.all([
+      dispatch(tagUsers([accountId], diff.added)),
+      dispatch(untagUsers([accountId], diff.removed)),
+    ]);
+  };
+
+/** Synchronizes badges to the backend. */
+const setBadges = (accountId: string, oldTags: string[], newTags: string[]) =>
+  (dispatch: AppDispatch) => {
+    const oldBadges = filterBadges(oldTags);
+    const newBadges = filterBadges(newTags);
+
+    return dispatch(setTags(accountId, oldBadges, newBadges));
+  };
+
 const verifyUser = (accountId: string) =>
   (dispatch: AppDispatch) =>
     dispatch(tagUsers([accountId], ['verified']));
@@ -579,6 +600,8 @@ export {
   fetchModerationLog,
   tagUsers,
   untagUsers,
+  setTags,
+  setBadges,
   verifyUser,
   unverifyUser,
   setDonor,
diff --git a/app/soapbox/components/ui/index.ts b/app/soapbox/components/ui/index.ts
index 5eff0a78f..fd9cb055e 100644
--- a/app/soapbox/components/ui/index.ts
+++ b/app/soapbox/components/ui/index.ts
@@ -34,6 +34,7 @@ export { default as Select } from './select/select';
 export { default as Spinner } from './spinner/spinner';
 export { default as Stack } from './stack/stack';
 export { default as Tabs } from './tabs/tabs';
+export { default as TagInput } from './tag-input/tag-input';
 export { default as Text } from './text/text';
 export { default as Textarea } from './textarea/textarea';
 export { default as Toggle } from './toggle/toggle';
diff --git a/app/soapbox/components/ui/tag-input/tag-input.tsx b/app/soapbox/components/ui/tag-input/tag-input.tsx
index b692e82e9..e4f8548ab 100644
--- a/app/soapbox/components/ui/tag-input/tag-input.tsx
+++ b/app/soapbox/components/ui/tag-input/tag-input.tsx
@@ -43,7 +43,7 @@ const TagInput: React.FC<ITagInput> = ({ tags, onChange, placeholder }) => {
   };
 
   return (
-    <div className='mt-1 relative shadow-sm'>
+    <div className='mt-1 relative shadow-sm flex-grow'>
       <HStack
         className='p-2 pb-0 text-gray-900 dark:text-gray-100 placeholder:text-gray-600 dark:placeholder:text-gray-600 block w-full sm:text-sm dark:ring-1 dark:ring-gray-800 focus:ring-primary-500 focus:border-primary-500 dark:focus:ring-primary-500 dark:focus:border-primary-500 rounded-md bg-white dark:bg-gray-900 border-gray-400 dark:border-gray-800'
         space={2}
@@ -56,7 +56,7 @@ const TagInput: React.FC<ITagInput> = ({ tags, onChange, placeholder }) => {
         ))}
 
         <input
-          className='p-1 mb-2 h-8 flex-grow bg-transparent outline-none'
+          className='p-1 mb-2 w-32 h-8 flex-grow bg-transparent outline-none'
           value={input}
           placeholder={placeholder}
           onChange={e => setInput(e.target.value)}
diff --git a/app/soapbox/features/ui/components/modals/account-moderation-modal/account-moderation-modal.tsx b/app/soapbox/features/ui/components/modals/account-moderation-modal/account-moderation-modal.tsx
index be3c01d2c..d9d104b84 100644
--- a/app/soapbox/features/ui/components/modals/account-moderation-modal/account-moderation-modal.tsx
+++ b/app/soapbox/features/ui/components/modals/account-moderation-modal/account-moderation-modal.tsx
@@ -1,4 +1,4 @@
-import React, { ChangeEventHandler } from 'react';
+import React, { ChangeEventHandler, useState } from 'react';
 import { defineMessages, FormattedMessage, useIntl } from 'react-intl';
 
 import {
@@ -8,6 +8,7 @@ import {
   removeDonor,
   suggestUsers,
   unsuggestUsers,
+  setBadges as saveBadges,
 } from 'soapbox/actions/admin';
 import { deactivateUserModal, deleteUserModal } from 'soapbox/actions/moderation';
 import snackbar from 'soapbox/actions/snackbar';
@@ -18,7 +19,9 @@ import { Button, Text, HStack, Modal, Stack, Toggle } from 'soapbox/components/u
 import { useAppDispatch, useAppSelector, useFeatures, useOwnAccount } from 'soapbox/hooks';
 import { makeGetAccount } from 'soapbox/selectors';
 import { isLocal } from 'soapbox/utils/accounts';
+import { getBadges } from 'soapbox/utils/badges';
 
+import BadgeInput from './badge-input';
 import StaffRolePicker from './staff-role-picker';
 
 const getAccount = makeGetAccount();
@@ -30,6 +33,7 @@ const messages = defineMessages({
   removeDonorSuccess: { id: 'admin.users.remove_donor_message', defaultMessage: '@{acct} was removed as a donor' },
   userSuggested: { id: 'admin.users.user_suggested_message', defaultMessage: '@{acct} was suggested' },
   userUnsuggested: { id: 'admin.users.user_unsuggested_message', defaultMessage: '@{acct} was unsuggested' },
+  badgesSaved: { id: 'admin.users.badges_saved_message', defaultMessage: 'Custom badges updated.' },
 });
 
 interface IAccountModerationModal {
@@ -48,6 +52,9 @@ const AccountModerationModal: React.FC<IAccountModerationModal> = ({ onClose, ac
   const features = useFeatures();
   const account = useAppSelector(state => getAccount(state, accountId));
 
+  const accountBadges = account ? getBadges(account) : [];
+  const [badges, setBadges] = useState<string[]>(accountBadges);
+
   const handleClose = () => onClose('ACCOUNT_MODERATION');
 
   if (!account || !ownAccount) {
@@ -103,6 +110,12 @@ const AccountModerationModal: React.FC<IAccountModerationModal> = ({ onClose, ac
     dispatch(deleteUserModal(intl, account.id));
   };
 
+  const handleSaveBadges = () => {
+    dispatch(saveBadges(account.id, accountBadges, badges))
+      .then(() => dispatch(snackbar.success(intl.formatMessage(messages.badgesSaved))))
+      .catch(() => {});
+  };
+
   return (
     <Modal
       title={<FormattedMessage id='account_moderation_modal.title' defaultMessage='Moderate @{acct}' values={{ acct: account.acct }} />}
@@ -149,6 +162,17 @@ const AccountModerationModal: React.FC<IAccountModerationModal> = ({ onClose, ac
               />
             </ListItem>
           )}
+
+          <ListItem label={<FormattedMessage id='account_moderation_modal.fields.badges' defaultMessage='Custom badges' />}>
+            <div className='flex-grow'>
+              <HStack className='w-full' alignItems='center' space={2}>
+                <BadgeInput badges={badges} onChange={setBadges} />
+                <Button onClick={handleSaveBadges}>
+                  <FormattedMessage id='save' defaultMessage='Save' />
+                </Button>
+              </HStack>
+            </div>
+          </ListItem>
         </List>
 
         <List>
diff --git a/app/soapbox/features/ui/components/modals/account-moderation-modal/badge-input.tsx b/app/soapbox/features/ui/components/modals/account-moderation-modal/badge-input.tsx
new file mode 100644
index 000000000..63ef22fad
--- /dev/null
+++ b/app/soapbox/features/ui/components/modals/account-moderation-modal/badge-input.tsx
@@ -0,0 +1,37 @@
+import React from 'react';
+import { useIntl, defineMessages } from 'react-intl';
+
+import { TagInput } from 'soapbox/components/ui';
+import { badgeToTag, tagToBadge } from 'soapbox/utils/badges';
+
+const messages = defineMessages({
+  placeholder: { id: 'badge_input.placeholder', defaultMessage: 'Enter a badge…' },
+});
+
+interface IBadgeInput {
+  /** A badge is a tag that begins with `badge:` */
+  badges: string[],
+  /** Callback when badges change. */
+  onChange: (badges: string[]) => void,
+}
+
+/** Manages user badges. */
+const BadgeInput: React.FC<IBadgeInput> = ({ badges, onChange }) => {
+  const intl = useIntl();
+  const tags = badges.map(badgeToTag);
+
+  const handleTagsChange = (tags: string[]) => {
+    const badges = tags.map(tagToBadge);
+    onChange(badges);
+  };
+
+  return (
+    <TagInput
+      tags={tags}
+      onChange={handleTagsChange}
+      placeholder={intl.formatMessage(messages.placeholder)}
+    />
+  );
+};
+
+export default BadgeInput;
\ No newline at end of file
diff --git a/app/soapbox/utils/badges.ts b/app/soapbox/utils/badges.ts
new file mode 100644
index 000000000..139537f6f
--- /dev/null
+++ b/app/soapbox/utils/badges.ts
@@ -0,0 +1,47 @@
+import { OrderedSet as ImmutableOrderedSet } from 'immutable';
+
+import type { Account } from 'soapbox/types/entities';
+
+/** Convert a plain tag into a badge. */
+const tagToBadge = (tag: string) => `badge:${tag}`;
+
+/** Convert a badge into a plain tag. */
+const badgeToTag = (badge: string) => badge.replace(/^badge:/, '');
+
+/** Difference between an old and new set of tags. */
+interface TagDiff {
+  /** New tags that were added. */
+  added: string[],
+  /** Old tags that were removed. */
+  removed: string[],
+}
+
+/** Returns the differences between two sets of tags. */
+const getTagDiff = (oldTags: string[], newTags: string[]): TagDiff => {
+  const o = ImmutableOrderedSet(oldTags);
+  const n = ImmutableOrderedSet(newTags);
+
+  return {
+    added: n.subtract(o).toArray(),
+    removed: o.subtract(n).toArray(),
+  };
+};
+
+/** Returns only tags which are badges. */
+const filterBadges = (tags: string[]): string[] => {
+  return tags.filter(tag => tag.startsWith('badge:'));
+};
+
+/** Get badges from an account. */
+const getBadges = (account: Account) => {
+  const tags = Array.from(account?.getIn(['pleroma', 'tags']) as Iterable<string> || []);
+  return filterBadges(tags);
+};
+
+export {
+  tagToBadge,
+  badgeToTag,
+  filterBadges,
+  getTagDiff,
+  getBadges,
+};
\ No newline at end of file