diff --git a/src/components/structures/MatrixChat.tsx b/src/components/structures/MatrixChat.tsx
index d9ed7d061b..078b296295 100644
--- a/src/components/structures/MatrixChat.tsx
+++ b/src/components/structures/MatrixChat.tsx
@@ -1096,8 +1096,22 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
         const roomToLeave = MatrixClientPeg.get().getRoom(roomId);
         const isSpace = roomToLeave?.isSpaceRoom();
         // Show a warning if there are additional complications.
-        const joinRules = roomToLeave.currentState.getStateEvents('m.room.join_rules', '');
         const warnings = [];
+
+        const memberCount = roomToLeave.currentState.getJoinedMemberCount();
+        if (memberCount === 1) {
+            warnings.push((
+                <span className="warning" key="only_member_warning">
+                    {' '/* Whitespace, otherwise the sentences get smashed together */ }
+                    { _t("You are the only person here. " +
+                        "If you leave, no one will be able to join in the future, including you.") }
+                </span>
+            ));
+
+            return warnings;
+        }
+
+        const joinRules = roomToLeave.currentState.getStateEvents('m.room.join_rules', '');
         if (joinRules) {
             const rule = joinRules.getContent().join_rule;
             if (rule !== "public") {
diff --git a/src/i18n/strings/en_EN.json b/src/i18n/strings/en_EN.json
index f2feef63b9..133d24e3c8 100644
--- a/src/i18n/strings/en_EN.json
+++ b/src/i18n/strings/en_EN.json
@@ -2556,6 +2556,7 @@
     "Failed to reject invitation": "Failed to reject invitation",
     "Cannot create rooms in this community": "Cannot create rooms in this community",
     "You do not have permission to create rooms in this community.": "You do not have permission to create rooms in this community.",
+    "You are the only person here. If you leave, no one will be able to join in the future, including you.": "You are the only person here. If you leave, no one will be able to join in the future, including you.",
     "This space is not public. You will not be able to rejoin without an invite.": "This space is not public. You will not be able to rejoin without an invite.",
     "This room is not public. You will not be able to rejoin without an invite.": "This room is not public. You will not be able to rejoin without an invite.",
     "Are you sure you want to leave the space '%(spaceName)s'?": "Are you sure you want to leave the space '%(spaceName)s'?",