diff --git a/CHANGELOG.md b/CHANGELOG.md
index 828f51aa..6a16da7d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -44,6 +44,9 @@
 * Kitty keyboard protocol:
   - [Report event types](https://sw.kovidgoyal.net/kitty/keyboard-protocol/#report-events)
     (mode `0b10`)
+  - [Report alternate keys](https://sw.kovidgoyal.net/kitty/keyboard-protocol/#report-alternates)
+    (mode `0b100`, but not that only the _shifted_ key is reported,
+    not the _base layout key_)
   - [Report all keys as escape codes](https://sw.kovidgoyal.net/kitty/keyboard-protocol/#report-all-keys)
     (mode `0b1000`)
   - [Report associated text](https://sw.kovidgoyal.net/kitty/keyboard-protocol/#report-text)
diff --git a/input.c b/input.c
index 869e1c67..41349d9a 100644
--- a/input.c
+++ b/input.c
@@ -1161,6 +1161,7 @@ kitty_kbd_protocol(struct seat *seat, struct terminal *term,
 
     const bool disambiguate = flags & KITTY_KBD_DISAMBIGUATE;
     const bool report_events = flags & KITTY_KBD_REPORT_EVENT;
+    const bool report_alternate = flags & KITTY_KBD_REPORT_ALTERNATE;
     const bool report_all_as_escapes = flags & KITTY_KBD_REPORT_ALL;
 
     if (!report_events && released)
@@ -1252,7 +1253,7 @@ emit_escapes:
         encoded_mods |= mods & (1 << seat->kbd.mod_num)   ? (1 << 7) : 0;
     encoded_mods++;
 
-    int key = -1;
+    int key = -1, alternate = -1, base = -1;
     char final;
 
     switch (sym) {
@@ -1435,8 +1436,22 @@ emit_escapes:
             key = xkb_keysym_to_utf32(sym_to_use);
             if (key == 0)
                 key = sym_to_use;
+
+            /* The *shifted* key. May be the same as the unshifted
+             * key - if so, this is filtered out below, when
+             * emitting the CSI */
+            alternate = xkb_keysym_to_utf32(sym);
         }
 
+        /* Base layout key. I.e the symbol the pressed key produces in
+         * the base/default layout (layout idx 0) */
+        const xkb_keysym_t *base_syms;
+        int base_sym_count = xkb_keymap_key_get_syms_by_level(
+            seat->kbd.xkb_keymap, ctx->key, 0, 0, &base_syms);
+
+        if (base_sym_count > 0)
+            base = xkb_keysym_to_utf32(base_syms[0]);
+
         final = 'u';
         break;
     }
@@ -1445,7 +1460,7 @@ emit_escapes:
     xassert(encoded_mods >= 1);
 
     char event[4];
-    if (report_events) {
+    if (report_events /*&& !pressed*/) {
         /* Note: this deviates slightly from Kitty, which omits the
          * “:1” subparameter for key press events */
         event[0] = ':';
@@ -1465,14 +1480,32 @@ emit_escapes:
         bytes = snprintf(p, left, "\x1b[%u", key);
         p += bytes; left -= bytes;
 
-        if (encoded_mods > 1 || event[0] != '\0' || report_associated_text) {
-            bytes = snprintf(p, left, ";%u%s", encoded_mods, event);
-            p += bytes; left -= bytes;
+        if (report_alternate) {
+            bool emit_alternate = alternate > 0 && alternate != key;
+            bool emit_base = base > 0 && base != key && base != alternate;
 
-            if (report_associated_text) {
-                bytes = snprintf(p, left, ";%u", utf32);
+            if (emit_alternate) {
+                bytes = snprintf(p, left, ":%u", alternate);
                 p += bytes; left -= bytes;
             }
+
+            if (emit_base) {
+                bytes = snprintf(
+                    p, left, "%s:%u", !emit_alternate ? ":" : "", base);
+                p += bytes; left -= bytes;
+            }
+        }
+
+        bool emit_mods = encoded_mods > 1 || event[0] != '\0';
+
+        if (emit_mods) {
+            bytes = snprintf(p, left, ";%u%s", encoded_mods, event);
+            p += bytes; left -= bytes;
+        }
+
+        if (report_associated_text) {
+            bytes = snprintf(p, left, "%s;%u", !emit_mods ? ";" : "", utf32);
+            p += bytes; left -= bytes;
         }
 
         bytes = snprintf(p, left, "%c", final);
diff --git a/terminal.h b/terminal.h
index 394871f6..09b04614 100644
--- a/terminal.h
+++ b/terminal.h
@@ -135,6 +135,7 @@ enum kitty_kbd_flags {
     KITTY_KBD_REPORT_ASSOCIATED = 0x10,
     KITTY_KBD_SUPPORTED = (KITTY_KBD_DISAMBIGUATE |
                            KITTY_KBD_REPORT_EVENT |
+                           KITTY_KBD_REPORT_ALTERNATE |
                            KITTY_KBD_REPORT_ALL |
                            KITTY_KBD_REPORT_ASSOCIATED),
 };