diff --git a/pkg/hicli/json-commands.go b/pkg/hicli/json-commands.go
index 0a07c25..9be033a 100644
--- a/pkg/hicli/json-commands.go
+++ b/pkg/hicli/json-commands.go
@@ -86,6 +86,10 @@ func (h *HiClient) handleJSONCommand(ctx context.Context, req *JSONCommand) (any
 		return unmarshalAndCall(req.Data, func(params *getProfileParams) (*mautrix.RespUserProfile, error) {
 			return h.Client.GetProfile(ctx, params.UserID)
 		})
+	case "set_profile_field":
+		return unmarshalAndCall(req.Data, func(params *setProfileFieldParams) (bool, error) {
+			return true, h.Client.UnstableSetProfileField(ctx, params.Field, params.Value)
+		})
 	case "get_mutual_rooms":
 		return unmarshalAndCall(req.Data, func(params *getProfileParams) ([]id.RoomID, error) {
 			return h.GetMutualRooms(ctx, params.UserID)
@@ -273,6 +277,11 @@ type getProfileParams struct {
 	UserID id.UserID `json:"user_id"`
 }
 
+type setProfileFieldParams struct {
+	Field string `json:"field"`
+	Value any    `json:"value"`
+}
+
 type getEventParams struct {
 	RoomID  id.RoomID  `json:"room_id"`
 	EventID id.EventID `json:"event_id"`
diff --git a/web/src/api/rpc.ts b/web/src/api/rpc.ts
index b967010..df9131f 100644
--- a/web/src/api/rpc.ts
+++ b/web/src/api/rpc.ts
@@ -39,7 +39,7 @@ import type {
 	RoomSummary,
 	TimelineRowID,
 	UserID,
-	UserProfile,
+	UserProfile, JSONValue,
 } from "./types"
 
 export interface ConnectionEvent {
@@ -180,6 +180,10 @@ export default abstract class RPCClient {
 		return this.request("get_profile", { user_id })
 	}
 
+	setProfileField(field: string, value: JSONValue): Promise<boolean> {
+		return this.request("set_profile_field", { field, value })
+	}
+
 	getMutualRooms(user_id: UserID): Promise<RoomID[]> {
 		return this.request("get_mutual_rooms", { user_id })
 	}
diff --git a/web/src/api/types/mxtypes.ts b/web/src/api/types/mxtypes.ts
index 5932e3e..e91ad02 100644
--- a/web/src/api/types/mxtypes.ts
+++ b/web/src/api/types/mxtypes.ts
@@ -25,6 +25,14 @@ export type RoomVersion = "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" |
 export type RoomType = "" | "m.space"
 export type RelationType = "m.annotation" | "m.reference" | "m.replace" | "m.thread"
 
+export type JSONValue =
+	| string
+	| number
+	| boolean
+	| null
+	| JSONValue[]
+	| {[key: string]: JSONValue}
+
 export interface RoomPredecessor {
 	room_id: RoomID
 	event_id: EventID
diff --git a/web/src/ui/rightpanel/RightPanel.css b/web/src/ui/rightpanel/RightPanel.css
index efb0b70..71ab3de 100644
--- a/web/src/ui/rightpanel/RightPanel.css
+++ b/web/src/ui/rightpanel/RightPanel.css
@@ -72,6 +72,13 @@ div.right-panel-content.user {
 		}
 	}
 
+	input.text-input {
+		border: 0;
+		width: 100%;
+		box-sizing: border-box;
+		border-bottom: 1px solid var(--blockquote-border-color);
+	}
+
 	div.displayname {
 		font-size: 1.5rem;
 		font-weight: bold;
@@ -92,14 +99,9 @@ div.right-panel-content.user {
 	}
 
 	div.extended-profile {
-		display: flex;
-		flex-direction: column;
+		display: grid;
 		gap: 0.25rem;
-
-		div.profile-row {
-			display: grid;
-			grid-template-columns: 1fr 1fr;
-		}
+		grid-template-columns: 1fr 1fr;
 	}
 
 	hr {
diff --git a/web/src/ui/rightpanel/UserExtendedProfile.tsx b/web/src/ui/rightpanel/UserExtendedProfile.tsx
index 8d03a29..aa9bde3 100644
--- a/web/src/ui/rightpanel/UserExtendedProfile.tsx
+++ b/web/src/ui/rightpanel/UserExtendedProfile.tsx
@@ -1,6 +1,7 @@
 import { useEffect, useState } from "react"
 import { UserProfile } from "@/api/types"
 import { ensureArray } from "@/util/validation.ts"
+import Client from "@/api/client.ts";
 
 interface PronounSet {
 	subject: string
@@ -18,13 +19,25 @@ interface ExtendedProfileAttributes {
 
 interface ExtendedProfileProps {
 	profile: UserProfile & ExtendedProfileAttributes
+	client: Client
+	userID: string
 }
 
+interface SetTimezoneProps {
+	tz?: string
+	client: Client
+}
+
+const getCurrentTimezone = () => Intl.DateTimeFormat().resolvedOptions().timeZone
 
 const currentTimeAdjusted = (tz: string) => {
 	const lang = navigator.language || "en-US"
 	const now = new Date()
-	return new Intl.DateTimeFormat(lang, { timeStyle: "long", timeZone: tz }).format(now)
+	try {
+		return new Intl.DateTimeFormat(lang, { timeStyle: "long", timeZone: tz }).format(now)
+	} catch (e) {
+		return `Error: ${e}`
+	}
 }
 
 function ClockElement({ tz }: { tz: string }) {
@@ -38,37 +51,82 @@ function ClockElement({ tz }: { tz: string }) {
 	return <div>{time}</div>
 }
 
+function SetTimezoneElement({ tz, client }: SetTimezoneProps) {
+	const zones = Intl.supportedValuesOf("timeZone")
+	const setTz = (newTz: string) => {
+		if (zones.includes(newTz) && newTz !== tz) {
+			return client.rpc.setProfileField("us.cloke.msc4175.tz", newTz).then(
+				() => client.rpc.getProfile(client.userID),
+				(err) => console.error("Error setting timezone", err),
+			)
+		}
+	}
 
-export default function UserExtendedProfile({ profile }: ExtendedProfileProps) {
+	return (
+		<>
+			<input
+				list={"timezones"}
+				className={"text-input"}
+				defaultValue={tz || getCurrentTimezone()}
+				onChange={(e) => setTz(e.currentTarget.value)}
+			/>
+			<datalist id={"timezones"}>
+				{
+					zones.map((zone) => <option key={zone} value={zone} />)
+				}
+			</datalist>
+		</>
+	)
+}
+
+
+export default function UserExtendedProfile({ profile, client, userID }: ExtendedProfileProps) {
 	if (!profile) return null
 
+	const extendedProfileKeys = ["us.cloke.msc4175.tz", "io.fsky.nyx.pronouns"]
+	const hasExtendedProfile = extendedProfileKeys.some((key) => key in profile)
+	if (!hasExtendedProfile && client.userID !== userID) return null
+	// Explicitly only return something if the profile has the keys we're looking for.
+	// otherwise there's an ugly and pointless <hr/> for no real reason.
+
 	const pronouns: PronounSet[] = ensureArray(profile["io.fsky.nyx.pronouns"]) as PronounSet[]
 	return (
-		<div className={"extended-profile"}>
-			{
-				profile["us.cloke.msc4175.tz"] && (
-					<div className={"profile-row"}>
-						<div title={profile["us.cloke.msc4175.tz"]}>Time:</div>
-						<ClockElement tz={profile["us.cloke.msc4175.tz"]} />
-					</div>
-				)
-			}
-			{
-				pronouns.length >= 1 && (
-					<div className={"profile-row"}>
-						<div>Pronouns:</div>
-						<div>
-							{
-								pronouns.map(
-									(pronounSet: PronounSet) => (
-										pronounSet.summary || `${pronounSet.subject}/${pronounSet.object}`
-									),
-								).join("/")
-							}
-						</div>
-					</div>
-				)
-			}
-		</div>
+		<>
+			<hr/>
+			<div className={"extended-profile"}>
+				{
+					profile["us.cloke.msc4175.tz"] && (
+						<>
+							<div title={profile["us.cloke.msc4175.tz"]}>Time:</div>
+							<ClockElement tz={profile["us.cloke.msc4175.tz"]} />
+						</>
+					)
+				}
+				{
+					userID === client.userID && (
+						<>
+							<div>Set Timezone:</div>
+							<SetTimezoneElement tz={profile["us.cloke.msc4175.tz"]} client={client} />
+						</>
+					)
+				}
+				{
+					pronouns.length >= 1 && (
+						<>
+							<div>Pronouns:</div>
+							<div>
+								{
+									pronouns.map(
+										(pronounSet: PronounSet) => (
+											pronounSet.summary || `${pronounSet.subject}/${pronounSet.object}`
+										),
+									).join("/")
+								}
+							</div>
+						</>
+					)
+				}
+			</div>
+		</>
 	)
 }
diff --git a/web/src/ui/rightpanel/UserInfo.tsx b/web/src/ui/rightpanel/UserInfo.tsx
index 71d530f..fd4275a 100644
--- a/web/src/ui/rightpanel/UserInfo.tsx
+++ b/web/src/ui/rightpanel/UserInfo.tsx
@@ -47,6 +47,8 @@ const UserInfo = ({ userID }: UserInfoProps) => {
 			err => setErrors([`${err}`]),
 		)
 	}, [roomCtx, userID, client])
+
+
 	const displayname = member?.displayname || globalProfile?.displayname || getLocalpart(userID)
 	return <>
 		<div className="avatar-container">
@@ -63,7 +65,7 @@ const UserInfo = ({ userID }: UserInfoProps) => {
 		</div>
 		<div className="displayname" title={displayname}>{displayname}</div>
 		<div className="userid" title={userID}>{userID}</div>
-		{globalProfile && <><hr/><UserExtendedProfile profile={globalProfile}/></>}
+		{globalProfile && <UserExtendedProfile profile={globalProfile} client={client} userID={userID}/>}
 		<hr/>
 		{userID !== client.userID && <>
 			<MutualRooms client={client} userID={userID}/>