diff --git a/apps/web/public/app.js b/apps/web/public/app.js
index c910e8f..484c704 100644
--- a/apps/web/public/app.js
+++ b/apps/web/public/app.js
@@ -2,6 +2,53 @@
    form; this file localises times and adds push notifications and passkeys where the
    browser has them. */
 
+/* ----------------------------------------------------------- list filter -- */
+
+/**
+ * Filter a list of leagues or teams as you type.
+ *
+ * Every word must appear somewhere in the row's `data-filter` text, in any order
+ * and ignoring case: "city man" keeps Manchester City, "MAN" keeps it too. The
+ * box is server-rendered `hidden` and only shown here, so with JavaScript off
+ * nobody sees a control that does nothing.
+ */
+function listFilterWords(query) {
+  return String(query || '')
+    .toLocaleLowerCase()
+    .split(/\s+/)
+    .filter(Boolean);
+}
+
+function listFilterMatches(text, words) {
+  const hay = String(text || '').toLocaleLowerCase();
+  return words.every((w) => hay.includes(w));
+}
+
+function initListFilters(root = document) {
+  for (const box of root.querySelectorAll('[data-list-filter]')) {
+    if (box.dataset.ready) continue;
+    const list = document.getElementById(box.dataset.listFilter);
+    const input = box.querySelector('input');
+    if (!list || !input) continue;
+    box.dataset.ready = '1';
+    box.hidden = false;
+    const empty = box.querySelector('.list-filter-empty');
+    const apply = () => {
+      const words = listFilterWords(input.value);
+      let shown = 0;
+      for (const li of list.children) {
+        const ok = listFilterMatches(li.dataset.filter ?? li.textContent, words);
+        li.hidden = !ok;
+        if (ok) shown++;
+      }
+      if (empty) empty.hidden = shown > 0;
+    };
+    input.addEventListener('input', apply);
+    // A value the browser restored on back/forward must filter too.
+    if (input.value) apply();
+  }
+}
+
 /* ------------------------------------------------------------ local time -- */
 
 /**
@@ -880,6 +927,7 @@ function initNavigation() {
       if (push) history.pushState({}, '', url);
       window.scrollTo(0, 0);
       localiseTimes();
+      initListFilters();
       initMarketTabs();
       initOwnChannelActions();
       initInlinePlayer();
@@ -919,6 +967,7 @@ function initNavigation() {
 }
 
 localiseTimes();
+initListFilters();
 reportTimezone();
 initMarketTabs();
 initOwnChannelActions();
diff --git a/apps/web/public/styles.css b/apps/web/public/styles.css
index 9d7930d..43f4983 100644
--- a/apps/web/public/styles.css
+++ b/apps/web/public/styles.css
@@ -2956,4 +2956,20 @@ ul.group-grid .meta {
     --live: oklch(0.72 0.19 25);
     --ok: oklch(0.78 0.16 155);
   }
-}
\ No newline at end of file
+}
+/* ---- league / team list filter (shown by app.js) ---- */
+.list-filter {
+  margin: 0.75rem 0;
+}
+.list-filter input[type="search"] {
+  max-width: 24rem;
+}
+.list-filter-empty {
+  margin-top: 0.5rem;
+}
+ul.sports > li[hidden],
+ul.leagues > li[hidden],
+ul.teams > li[hidden],
+ul.chips > li[hidden] {
+  display: none;
+}
diff --git a/apps/web/src/views/components.jsx b/apps/web/src/views/components.jsx
index 463704d..bee360f 100644
--- a/apps/web/src/views/components.jsx
+++ b/apps/web/src/views/components.jsx
@@ -609,9 +609,27 @@ export const EventList = ({ events, emptyText, showBroadcast = false, showOdds =
     </ul>
   );
 
+/**
+ * A filter box for a list of leagues or teams.
+ *
+ * Every word typed has to appear in a row, in any order and ignoring case, so
+ * "city man" finds Manchester City. Rendered `hidden` and switched on by app.js:
+ * without JavaScript the box would do nothing, and a control that does nothing
+ * is worse than no control. Rows match on their `data-filter` text, which is the
+ * name alone, so "upcoming" or "follow" never matches every row.
+ */
+export const ListFilter = ({ target, label }) => (
+  <div class="list-filter" data-list-filter={target} hidden>
+    <input type="search" aria-label={label} placeholder={`${label}…`} autocomplete="off" />
+    <p class="muted small list-filter-empty" hidden>
+      Nothing matches.
+    </p>
+  </div>
+);
+
 /** A team in the follow picker. */
 export const TeamRow = ({ team, user, next }) => (
-  <li class="team">
+  <li class="team" data-filter={team.display_name}>
     {team.logo_url ? (
       <img src={team.logo_url} alt="" loading="lazy" width="28" height="28" />
     ) : (
diff --git a/apps/web/src/views/feeds.jsx b/apps/web/src/views/feeds.jsx
index ded6f27..21776a1 100644
--- a/apps/web/src/views/feeds.jsx
+++ b/apps/web/src/views/feeds.jsx
@@ -1,4 +1,5 @@
 import { brand, Word } from '@tipoff/config';
+import { ListFilter } from './components.jsx';
 import { Layout } from './Layout.jsx';
 
 /**
@@ -31,9 +32,10 @@ export const Feeds = ({ user, sports, leagues }) => (
     </ul>
 
     <h2>By {brand.words.category}</h2>
-    <ul class="sports">
+    <ListFilter target="feed-sports" label={`Filter ${brand.words.categories}`} />
+    <ul class="sports" id="feed-sports">
       {sports.map((s) => (
-        <li>
+        <li data-filter={s.sport.replace(/-/g, ' ')}>
           <a href={`/feeds/sport/${s.sport}.xml`}>
             <strong>{s.sport.replace(/-/g, ' ')}</strong>
             <span class="muted">
@@ -50,9 +52,10 @@ export const Feeds = ({ user, sports, leagues }) => (
       and a calendar at <code>/calendar/league/&lt;slug&gt;.ics</code>, whether or not it is listed
       here.
     </p>
-    <ul class="leagues">
+    <ListFilter target="feed-leagues" label={`Filter ${brand.words.collections}`} />
+    <ul class="leagues" id="feed-leagues">
       {leagues.map((l) => (
-        <li>
+        <li data-filter={l.name}>
           <a href={`/feeds/league/${l.slug}.xml`}>{l.name}</a>
           <span class="muted small">
             {l.upcoming} upcoming · <a href={`/calendar/league/${l.slug}.ics`}>calendar</a>
diff --git a/apps/web/src/views/pages.jsx b/apps/web/src/views/pages.jsx
index 0b47006..b99058b 100644
--- a/apps/web/src/views/pages.jsx
+++ b/apps/web/src/views/pages.jsx
@@ -1,6 +1,6 @@
 import { COLUMNS as PROFILE_COLUMNS, renderProfileFields } from '@profullstack/profile';
-import { brand, href, Word } from '@tipoff/config';
 import { keyVaultCardHtml } from '@profullstack/sealed-secrets/vault-card';
+import { brand, href, Word } from '@tipoff/config';
 import { raw } from 'hono/html';
 import { assetUrl } from '../lib/asset-version.js';
 import { coinpayConfig } from '../lib/coinpay-signin.js';
@@ -11,6 +11,7 @@ import {
   EventList,
   FollowButton,
   KickoffTime,
+  ListFilter,
   LocalTime,
   OddsPanel,
   oddsOf,
@@ -781,9 +782,10 @@ export const SportsIndex = ({
       <li>{Word.collection}</li>
       <li>{Word.participant}</li>
     </ol>
-    <ul class="sports">
+    <ListFilter target="sports-list" label={`Filter ${brand.words.categories}`} />
+    <ul class="sports" id="sports-list">
       {sports.map((s) => (
-        <li>
+        <li data-filter={`${categoryLabel(s.sport)} ${s.sport}`}>
           <a href={href.category(s.sport)}>
             <strong>{categoryLabel(s.sport)}</strong>
             <span class="muted">
@@ -1069,9 +1071,10 @@ export const SportPage = ({
         heading={`Watch ${name} now`}
         blurb="Live channels, playing here. No account, nothing to install."
       />
-      <ul class="leagues">
+      <ListFilter target="leagues-list" label={`Filter ${brand.words.collections}`} />
+      <ul class="leagues" id="leagues-list">
         {leagues.map((l) => (
-          <li>
+          <li data-filter={l.name}>
             <a href={href.collection(l.slug)}>{l.name}</a>
             <FollowButton
               user={user}
@@ -1173,11 +1176,14 @@ export const LeaguePage = ({
       {teams.length === 0 ? (
         <p class="empty">{brand.copy.emptyParticipants}</p>
       ) : (
-        <ul class="teams">
-          {teams.map((t) => (
-            <TeamRow team={t} user={user} next={href.collection(league.slug)} />
-          ))}
-        </ul>
+        <>
+          <ListFilter target="teams-list" label={`Filter ${brand.words.participants}`} />
+          <ul class="teams" id="teams-list">
+            {teams.map((t) => (
+              <TeamRow team={t} user={user} next={href.collection(league.slug)} />
+            ))}
+          </ul>
+        </>
       )}
 
       <h2>Upcoming fixtures</h2>
@@ -1539,9 +1545,10 @@ export const Following = ({ user, events, follows, cleared, calendarUrl }) => (
             </button>
           </form>
         </div>
-        <ul class="chips">
+        <ListFilter target="follows-list" label="Filter what you follow" />
+        <ul class="chips" id="follows-list">
           {follows.map((f) => (
-            <li class="chip">
+            <li class="chip" data-filter={f.label}>
               {f.label}
               <form method="post" action="/api/unfollow" class="inline">
                 <input type="hidden" name="subject_type" value={f.subject_type} />
@@ -3236,7 +3243,13 @@ export const Settings = ({
       {contactError ? <p class="feedback error">{contactError}</p> : null}
       {contactSaved ? <p class="feedback ok">Contact details saved.</p> : null}
       <form method="post" action="/api/settings/contact">
-        {raw(renderProfileFields({ fields: SIGNUP_FIELDS, values: contact ?? {}, importOpenProfile: true }))}
+        {raw(
+          renderProfileFields({
+            fields: SIGNUP_FIELDS,
+            values: contact ?? {},
+            importOpenProfile: true,
+          }),
+        )}
         <div class="form-actions">
           <button class="cta" type="submit">
             Save contact details
diff --git a/apps/web/test/list-filter.test.jsx b/apps/web/test/list-filter.test.jsx
new file mode 100644
index 0000000..d71d5b3
--- /dev/null
+++ b/apps/web/test/list-filter.test.jsx
@@ -0,0 +1,92 @@
+import { describe, expect, test } from 'bun:test';
+import { readFileSync } from 'node:fs';
+
+process.env.DATABASE_URL ??= 'postgres://localhost:5432/unused';
+
+const { LeaguePage, SportPage, SportsIndex, Following } = await import('../src/views/pages.jsx');
+const { Feeds } = await import('../src/views/feeds.jsx');
+const html = async (node) => String(await node.toString());
+
+/*
+ * The matcher lives in public/app.js, a plain browser script with no exports, so
+ * the two pure helpers are pulled out of its source and evaluated on their own.
+ */
+const appSrc = readFileSync(new URL('../public/app.js', import.meta.url).pathname, 'utf8');
+const grab = (name) => {
+  const start = appSrc.indexOf(`function ${name}(`);
+  const end = appSrc.indexOf('\n}\n', start);
+  return appSrc.slice(start, end + 2);
+};
+const { listFilterWords, listFilterMatches } = new Function(
+  `${grab('listFilterWords')}\n${grab('listFilterMatches')}\nreturn { listFilterWords, listFilterMatches };`,
+)();
+const matches = (text, q) => listFilterMatches(text, listFilterWords(q));
+
+describe('list filter matcher', () => {
+  test('every word, any order, any case', () => {
+    expect(matches('Manchester City', 'city man')).toBe(true);
+    expect(matches('Manchester City', 'MAN')).toBe(true);
+    expect(matches('Manchester City', 'CiTy   MANCHESTER')).toBe(true);
+    expect(matches('Manchester City', 'city united')).toBe(false);
+    expect(matches('English Premier League', 'league prem')).toBe(true);
+  });
+  test('an empty query keeps every row', () => {
+    expect(matches('Anything', '')).toBe(true);
+    expect(matches('Anything', '   ')).toBe(true);
+  });
+});
+
+describe('filter boxes on every league and team list', () => {
+  const user = { id: 'u1', email: 'a@example.test' };
+  const team = { id: 't1', slug: 'man-city', display_name: 'Manchester City', upcoming: 2 };
+  const league = { id: 'l1', slug: 'eng.1', name: 'English Premier League', sport: 'soccer' };
+
+  test('a league page filters its teams', async () => {
+    const out = await html(
+      <LeaguePage user={user} league={league} teams={[team]} events={[]} following={false} />,
+    );
+    expect(out).toContain('data-list-filter="teams-list"');
+    expect(out).toContain('id="teams-list"');
+    expect(out).toContain('data-filter="Manchester City"');
+  });
+
+  test('a sport page filters its leagues', async () => {
+    const out = await html(<SportPage user={user} sport="soccer" leagues={[league]} />);
+    expect(out).toContain('data-list-filter="leagues-list"');
+    expect(out).toContain('data-filter="English Premier League"');
+  });
+
+  test('the sports index filters its sports', async () => {
+    const out = await html(<SportsIndex user={null} sports={[{ sport: 'soccer', leagues: 3 }]} />);
+    expect(out).toContain('data-list-filter="sports-list"');
+    expect(out).toContain('id="sports-list"');
+  });
+
+  test('the feeds page filters sports and leagues', async () => {
+    const out = await html(
+      <Feeds
+        user={null}
+        sports={[{ sport: 'soccer', leagues: 3 }]}
+        leagues={[{ ...league, upcoming: 4 }]}
+      />,
+    );
+    expect(out).toContain('data-list-filter="feed-sports"');
+    expect(out).toContain('data-list-filter="feed-leagues"');
+  });
+
+  test('following filters what you follow', async () => {
+    const out = await html(
+      <Following
+        user={user}
+        events={[]}
+        follows={[{ subject_type: 'team', subject_id: 't1', label: 'Manchester City' }]}
+      />,
+    );
+    expect(out).toContain('data-list-filter="follows-list"');
+  });
+
+  test('the box ships hidden so it never shows without JavaScript', async () => {
+    const out = await html(<SportPage user={user} sport="soccer" leagues={[league]} />);
+    expect(out).toMatch(/data-list-filter="leagues-list"[^>]*hidden/);
+  });
+});
diff --git a/package.json b/package.json
index f069ba8..f0540f8 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "tipoffwatch.com",
-  "version": "0.27.0",
+  "version": "0.28.0",
   "private": true,
   "type": "module",
   "description": "Sports calendar and reminder PWA. Follow any team in the world, get told before they play.",