diff --git a/app/javascript/flavours/glitch/features/account_timeline/index.js b/app/javascript/flavours/glitch/features/account_timeline/index.js
index 9f2a66881f3..6d4ebd34108 100644
--- a/app/javascript/flavours/glitch/features/account_timeline/index.js
+++ b/app/javascript/flavours/glitch/features/account_timeline/index.js
@@ -17,11 +17,12 @@ import MissingIndicator from 'flavours/glitch/components/missing_indicator';
 import TimelineHint from 'flavours/glitch/components/timeline_hint';
 import LimitedAccountHint from './components/limited_account_hint';
 import { getAccountHidden } from 'flavours/glitch/selectors';
+import { normalizeForLookup } from 'flavours/glitch/reducers/accounts_map';
 
 const emptyList = ImmutableList();
 
 const mapStateToProps = (state, { params: { acct, id }, withReplies = false }) => {
-  const accountId = id || state.getIn(['accounts_map', acct]);
+  const accountId = id || state.getIn(['accounts_map', normalizeForLookup(acct)]);
 
   if (!accountId) {
     return {
diff --git a/app/javascript/flavours/glitch/reducers/accounts_map.js b/app/javascript/flavours/glitch/reducers/accounts_map.js
index e0d42e9cd44..53e08c8fbe4 100644
--- a/app/javascript/flavours/glitch/reducers/accounts_map.js
+++ b/app/javascript/flavours/glitch/reducers/accounts_map.js
@@ -1,14 +1,16 @@
 import { ACCOUNT_IMPORT, ACCOUNTS_IMPORT } from '../actions/importer';
 import { Map as ImmutableMap } from 'immutable';
 
+export const normalizeForLookup = str => str.toLowerCase();
+
 const initialState = ImmutableMap();
 
 export default function accountsMap(state = initialState, action) {
   switch(action.type) {
   case ACCOUNT_IMPORT:
-    return state.set(action.account.acct, action.account.id);
+    return state.set(normalizeForLookup(action.account.acct), action.account.id);
   case ACCOUNTS_IMPORT:
-    return state.withMutations(map => action.accounts.forEach(account => map.set(account.acct, account.id)));
+    return state.withMutations(map => action.accounts.forEach(account => map.set(normalizeForLookup(account.acct), account.id)));
   default:
     return state;
   }