diff --git a/web/components/groups/group-selector.tsx b/web/components/groups/group-selector.tsx
index 6bc943dc..ea1597f2 100644
--- a/web/components/groups/group-selector.tsx
+++ b/web/components/groups/group-selector.tsx
@@ -22,7 +22,7 @@ export function GroupSelector(props: {
   const [isCreatingNewGroup, setIsCreatingNewGroup] = useState(false)
 
   const [query, setQuery] = useState('')
-  const memberGroups = useMemberGroups(creator)
+  const memberGroups = useMemberGroups(creator?.id)
   const filteredGroups = memberGroups
     ? query === ''
       ? memberGroups
diff --git a/web/components/groups/groups-button.tsx b/web/components/groups/groups-button.tsx
new file mode 100644
index 00000000..e6ee217d
--- /dev/null
+++ b/web/components/groups/groups-button.tsx
@@ -0,0 +1,144 @@
+import clsx from 'clsx'
+import { User } from 'common/user'
+import { useState } from 'react'
+import { useUser } from 'web/hooks/use-user'
+import { withTracking } from 'web/lib/service/analytics'
+import { Row } from 'web/components/layout/row'
+import { useMemberGroups } from 'web/hooks/use-group'
+import { TextButton } from 'web/components/text-button'
+import { Group } from 'common/group'
+import { Modal } from 'web/components/layout/modal'
+import { Col } from 'web/components/layout/col'
+import { joinGroup, leaveGroup } from 'web/lib/firebase/groups'
+import { firebaseLogin } from 'web/lib/firebase/users'
+import { GroupLink } from 'web/pages/groups'
+
+export function GroupsButton(props: { user: User }) {
+  const { user } = props
+  const [isOpen, setIsOpen] = useState(false)
+  const groups = useMemberGroups(user.id)
+
+  return (
+    <>
+      <TextButton onClick={() => setIsOpen(true)}>
+        <span className="font-semibold">{groups?.length ?? ''}</span> Groups
+      </TextButton>
+
+      <GroupsDialog
+        user={user}
+        groups={groups ?? []}
+        isOpen={isOpen}
+        setIsOpen={setIsOpen}
+      />
+    </>
+  )
+}
+
+function GroupsDialog(props: {
+  user: User
+  groups: Group[]
+  isOpen: boolean
+  setIsOpen: (isOpen: boolean) => void
+}) {
+  const { user, groups, isOpen, setIsOpen } = props
+
+  return (
+    <Modal open={isOpen} setOpen={setIsOpen}>
+      <Col className="rounded bg-white p-6">
+        <div className="p-2 pb-1 text-xl">{user.name}</div>
+        <div className="p-2 pt-0 text-sm text-gray-500">@{user.username}</div>
+        <GroupsList groups={groups} />
+      </Col>
+    </Modal>
+  )
+}
+
+function GroupsList(props: { groups: Group[] }) {
+  const { groups } = props
+  return (
+    <Col className="gap-2">
+      {groups.length === 0 && (
+        <div className="text-gray-500">No groups yet...</div>
+      )}
+      {groups
+        .sort((group1, group2) => group2.createdTime - group1.createdTime)
+        .map((group) => (
+          <GroupItem key={group.id} group={group} />
+        ))}
+    </Col>
+  )
+}
+
+function GroupItem(props: { group: Group; className?: string }) {
+  const { group, className } = props
+  return (
+    <Row className={clsx('items-center justify-between gap-2 p-2', className)}>
+      <Row className="line-clamp-1 items-center gap-2">
+        <GroupLink group={group} />
+      </Row>
+      <JoinOrLeaveGroupButton group={group} />
+    </Row>
+  )
+}
+
+export function JoinOrLeaveGroupButton(props: {
+  group: Group
+  small?: boolean
+  className?: string
+}) {
+  const { group, small, className } = props
+  const currentUser = useUser()
+  const isFollowing = currentUser
+    ? group.memberIds.includes(currentUser.id)
+    : false
+  const onJoinGroup = () => {
+    if (!currentUser) return
+    joinGroup(group, currentUser.id)
+  }
+  const onLeaveGroup = () => {
+    if (!currentUser) return
+    leaveGroup(group, currentUser.id)
+  }
+
+  const smallStyle =
+    'btn !btn-xs border-2 border-gray-500 bg-white normal-case text-gray-500 hover:border-gray-500 hover:bg-white hover:text-gray-500'
+
+  if (!currentUser || isFollowing === undefined) {
+    if (!group.anyoneCanJoin)
+      return <div className={clsx(className, 'text-gray-500')}>Closed</div>
+    return (
+      <button
+        onClick={firebaseLogin}
+        className={clsx('btn btn-sm', small && smallStyle, className)}
+      >
+        Login to Join
+      </button>
+    )
+  }
+
+  if (isFollowing) {
+    return (
+      <button
+        className={clsx(
+          'btn btn-outline btn-sm',
+          small && smallStyle,
+          className
+        )}
+        onClick={withTracking(onLeaveGroup, 'leave group')}
+      >
+        Leave
+      </button>
+    )
+  }
+
+  if (!group.anyoneCanJoin)
+    return <div className={clsx(className, 'text-gray-500')}>Closed</div>
+  return (
+    <button
+      className={clsx('btn btn-sm', small && smallStyle, className)}
+      onClick={withTracking(onJoinGroup, 'join group')}
+    >
+      Join
+    </button>
+  )
+}
diff --git a/web/components/nav/sidebar.tsx b/web/components/nav/sidebar.tsx
index e5f3cd5c..0b3d9393 100644
--- a/web/components/nav/sidebar.tsx
+++ b/web/components/nav/sidebar.tsx
@@ -185,7 +185,7 @@ export default function Sidebar(props: { className?: string }) {
   const mobileNavigationOptions = !user
     ? signedOutMobileNavigation
     : signedInMobileNavigation
-  const memberItems = (useMemberGroups(user) ?? []).map((group: Group) => ({
+  const memberItems = (useMemberGroups(user?.id) ?? []).map((group: Group) => ({
     name: group.name,
     href: groupPath(group.slug),
   }))
diff --git a/web/components/user-page.tsx b/web/components/user-page.tsx
index 2019a9de..246ed2aa 100644
--- a/web/components/user-page.tsx
+++ b/web/components/user-page.tsx
@@ -36,6 +36,7 @@ import { FollowersButton, FollowingButton } from './following-button'
 import { useFollows } from 'web/hooks/use-follows'
 import { FollowButton } from './follow-button'
 import { PortfolioMetrics } from 'common/user'
+import { GroupsButton } from 'web/components/groups/groups-button'
 
 export function UserLink(props: {
   name: string
@@ -197,6 +198,7 @@ export function UserPage(props: {
           <Row className="gap-4">
             <FollowingButton user={user} />
             <FollowersButton user={user} />
+            <GroupsButton user={user} />
           </Row>
 
           {user.website && (
diff --git a/web/hooks/use-group.ts b/web/hooks/use-group.ts
index f73fd04e..41f84707 100644
--- a/web/hooks/use-group.ts
+++ b/web/hooks/use-group.ts
@@ -29,11 +29,11 @@ export const useGroups = () => {
   return groups
 }
 
-export const useMemberGroups = (user: User | null | undefined) => {
+export const useMemberGroups = (userId: string | null | undefined) => {
   const [memberGroups, setMemberGroups] = useState<Group[] | undefined>()
   useEffect(() => {
-    if (user) return listenForMemberGroups(user.id, setMemberGroups)
-  }, [user])
+    if (userId) return listenForMemberGroups(userId, setMemberGroups)
+  }, [userId])
   return memberGroups
 }
 
diff --git a/web/lib/firebase/groups.ts b/web/lib/firebase/groups.ts
index 1438dd4c..d7244f98 100644
--- a/web/lib/firebase/groups.ts
+++ b/web/lib/firebase/groups.ts
@@ -94,3 +94,24 @@ export async function getGroupsWithContractId(
   const groups = await getValues<Group>(q)
   setGroups(groups)
 }
+
+export async function joinGroup(group: Group, userId: string): Promise<Group> {
+  const { memberIds } = group
+  if (memberIds.includes(userId)) {
+    return group
+  }
+  const newMemberIds = [...memberIds, userId]
+  const newGroup = { ...group, memberIds: newMemberIds }
+  await updateGroup(newGroup, { memberIds: newMemberIds })
+  return newGroup
+}
+export async function leaveGroup(group: Group, userId: string): Promise<Group> {
+  const { memberIds } = group
+  if (!memberIds.includes(userId)) {
+    return group
+  }
+  const newMemberIds = memberIds.filter((id) => id !== userId)
+  const newGroup = { ...group, memberIds: newMemberIds }
+  await updateGroup(newGroup, { memberIds: newMemberIds })
+  return newGroup
+}
diff --git a/web/pages/groups.tsx b/web/pages/groups.tsx
index c8f08b25..a8f99b23 100644
--- a/web/pages/groups.tsx
+++ b/web/pages/groups.tsx
@@ -15,6 +15,8 @@ import { getUser, User } from 'web/lib/firebase/users'
 import { Tabs } from 'web/components/layout/tabs'
 import { GroupMembersList } from 'web/pages/group/[...slugs]'
 import { checkAgainstQuery } from 'web/hooks/use-sort-and-query-params'
+import { SiteLink } from 'web/components/site-link'
+import clsx from 'clsx'
 
 export async function getStaticProps() {
   const groups = await listAllGroups().catch((_) => [])
@@ -202,3 +204,16 @@ export function GroupCard(props: { group: Group; creator: User | undefined }) {
     </Col>
   )
 }
+
+export function GroupLink(props: { group: Group; className?: string }) {
+  const { group, className } = props
+
+  return (
+    <SiteLink
+      href={groupPath(group.slug)}
+      className={clsx('z-10 truncate', className)}
+    >
+      {group.name}
+    </SiteLink>
+  )
+}