diff --git a/components/chat/ChatInput.vue b/components/chat/ChatInput.vue
index 44023d42..984906fb 100644
--- a/components/chat/ChatInput.vue
+++ b/components/chat/ChatInput.vue
@@ -108,22 +108,23 @@ const fieldName = `chat-message-${Math.random().toString(36).slice(2, 10)}`;
                   : 'flex items-center gap-2 p-2'
               "
             >
-              <Input
+              <Textarea
                 ref="inputRef"
+                rows="1"
                 :placeholder="activePlaceholder"
                 v-bind="componentField"
-                type="text"
                 autocomplete="off"
                 :name="fieldName"
                 data-1p-ignore="true"
                 data-lpignore="true"
                 data-bwignore="true"
                 data-form-type="other"
-                :class="
+                :class="[
+                  'min-h-0 resize-none py-1.5 leading-snug',
                   variant === 'global'
-                    ? 'flex-1 transition-all duration-200 focus:scale-[1.02]'
-                    : 'flex-1 resize-none border-0 shadow-none focus-visible:ring-0'
-                "
+                    ? 'flex-1 transition-[border-color,box-shadow] duration-200'
+                    : 'flex-1 border-0 shadow-none focus-visible:ring-0',
+                ]"
                 @keydown.enter="onEnter"
               />
               <Button
@@ -153,6 +154,7 @@ import { FormControl, FormField, FormItem } from "~/components/ui/form";
 import * as z from "zod";
 import { useForm } from "vee-validate";
 import { toTypedSchema } from "~/utilities/vee-validate-zod";
+import { chatEnterAction } from "~/utilities/chatInputKeys";
 
 export interface ChatInputChannel {
   value: string;
@@ -184,6 +186,14 @@ export default {
     },
   },
   emits: ["sendMessage", "update:destination"],
+  watch: {
+    // Not @input: v-bind="componentField" already binds one, and a second
+    // would replace vee-validate's. Watching the value also covers a paste and
+    // the reset after sending.
+    "form.values.message"() {
+      void this.$nextTick(() => this.growToFit());
+    },
+  },
   data() {
     return {
       sending: false,
@@ -279,20 +289,33 @@ export default {
     // the other room without moving them -- the common case is a single team
     // callout in the middle of talking to everyone.
     onEnter(event: KeyboardEvent) {
-      if (!event.metaKey && !event.ctrlKey) {
+      const action = chatEnterAction(event);
+
+      if (action === "newline") {
         return;
       }
 
-      if (!this.otherChannelValue) {
+      // The box is a textarea now, so nothing submits the form on its own.
+      event.preventDefault();
+
+      this.sendMessage(
+        action === "send-other" ? this.otherChannelValue : undefined,
+      );
+    },
+    // One line until the message needs more, then up to five.
+    growToFit() {
+      const field = this.$refs.inputRef?.$el ?? this.$refs.inputRef;
+
+      if (!field) {
         return;
       }
 
-      event.preventDefault();
-      this.sendMessage(this.otherChannelValue);
+      field.style.height = "auto";
+      field.style.height = `${Math.min(field.scrollHeight, 120)}px`;
     },
     sendMessage(destination?: string) {
-      const { message } = this.form.values;
-      if (!message || message?.length === 0) {
+      const message = this.form.values.message?.trim();
+      if (!message) {
         return;
       }
       this.$emit(
diff --git a/components/chat/ChatMessage.vue b/components/chat/ChatMessage.vue
index 9b5ae0a5..db20f631 100644
--- a/components/chat/ChatMessage.vue
+++ b/components/chat/ChatMessage.vue
@@ -73,7 +73,7 @@ import PlayerDisplay from "~/components/PlayerDisplay.vue";
           {{ $t("chat.team_tag") }}
         </span>
       </div>
-      <p class="text-[11px] leading-snug break-words">
+      <p class="text-[11px] leading-snug break-words whitespace-pre-wrap">
         {{ message.message }}
       </p>
     </div>
diff --git a/tests/utilities/chatInputKeys.spec.ts b/tests/utilities/chatInputKeys.spec.ts
new file mode 100644
index 00000000..e7aa4eee
--- /dev/null
+++ b/tests/utilities/chatInputKeys.spec.ts
@@ -0,0 +1,39 @@
+import { describe, expect, it } from "vitest";
+import { chatEnterAction } from "~/utilities/chatInputKeys";
+
+const key = (overrides: Partial<KeyboardEvent> = {}) =>
+  ({
+    shiftKey: false,
+    metaKey: false,
+    ctrlKey: false,
+    altKey: false,
+    isComposing: false,
+    ...overrides,
+  }) as KeyboardEvent;
+
+describe("chatEnterAction", () => {
+  it("sends on a bare enter", () => {
+    expect(chatEnterAction(key())).toBe("send");
+  });
+
+  it("makes a new line on shift+enter", () => {
+    expect(chatEnterAction(key({ shiftKey: true }))).toBe("newline");
+  });
+
+  it("sends to the other channel on ctrl or cmd enter", () => {
+    expect(chatEnterAction(key({ ctrlKey: true }))).toBe("send-other");
+    expect(chatEnterAction(key({ metaKey: true }))).toBe("send-other");
+  });
+
+  it("leaves an in-progress IME composition alone", () => {
+    // enter confirms the candidate in a Japanese or Korean IME; sending there
+    // would cut the word off mid-composition
+    expect(chatEnterAction(key({ isComposing: true }))).toBe("newline");
+  });
+
+  it("prefers the other channel over a new line when both modifiers are held", () => {
+    expect(chatEnterAction(key({ shiftKey: true, ctrlKey: true }))).toBe(
+      "send-other",
+    );
+  });
+});
diff --git a/utilities/chatInputKeys.ts b/utilities/chatInputKeys.ts
new file mode 100644
index 00000000..16ded467
--- /dev/null
+++ b/utilities/chatInputKeys.ts
@@ -0,0 +1,24 @@
+export type ChatEnterAction = "send" | "send-other" | "newline";
+
+/**
+ * What Enter means in the chat box.
+ *
+ * Enter sends, Shift+Enter breaks the line, and Ctrl/Cmd+Enter sends to the
+ * other room (match chat from team chat and back), which wins over a line break
+ * when both are held.
+ *
+ * A keypress that is confirming an IME candidate is never a send: in a Japanese
+ * or Korean composition Enter picks the word, and sending there would cut it
+ * off mid-word.
+ */
+export function chatEnterAction(event: KeyboardEvent): ChatEnterAction {
+  if (event.metaKey || event.ctrlKey) {
+    return "send-other";
+  }
+
+  if (event.isComposing) {
+    return "newline";
+  }
+
+  return event.shiftKey ? "newline" : "send";
+}