diff --git a/csi.c b/csi.c
index c1982275..80f2bfd0 100644
--- a/csi.c
+++ b/csi.c
@@ -470,6 +470,12 @@ decset_decrst(struct terminal *term, unsigned param, bool enable)
         term->meta.eight_bit = enable;
         break;
 
+    case 1035:
+        /* numLock */
+        LOG_DBG("%s Num Lock modifier", enable ? "enabling" : "disabling");
+        term->num_lock_modifier = enable;
+        break;
+
     case 1036:
         /* metaSendsEscape */
         LOG_DBG("%s meta-sends-escape", enable ? "enabling" : "disabling");
@@ -592,6 +598,7 @@ xtsave(struct terminal *term, unsigned param)
     case 1007: term->xtsave.alt_scrolling = term->alt_scrolling; break;
     case 1015: term->xtsave.mouse_urxvt = term->mouse_reporting == MOUSE_URXVT; break;
     case 1034: term->xtsave.meta_eight_bit = term->meta.eight_bit; break;
+    case 1035: term->xtsave.num_lock_modifier = term->num_lock_modifier; break;
     case 1036: term->xtsave.meta_esc_prefix = term->meta.esc_prefix; break;
     case 1042: term->xtsave.bell_is_urgent = term->bell_is_urgent; break;
     case 1049: term->xtsave.alt_screen = term->grid == &term->alt; break;
@@ -624,6 +631,7 @@ xtrestore(struct terminal *term, unsigned param)
     case 1007: enable = term->xtsave.alt_scrolling; break;
     case 1015: enable = term->xtsave.mouse_urxvt; break;
     case 1034: enable = term->xtsave.meta_eight_bit; break;
+    case 1035: enable = term->xtsave.num_lock_modifier; break;
     case 1036: enable = term->xtsave.meta_esc_prefix; break;
     case 1042: enable = term->xtsave.bell_is_urgent; break;
     case 1049: enable = term->xtsave.alt_screen; break;
diff --git a/terminal.c b/terminal.c
index b9e4528a..d117bf9c 100644
--- a/terminal.c
+++ b/terminal.c
@@ -1047,6 +1047,7 @@ term_init(const struct config *conf, struct fdm *fdm, struct reaper *reaper,
             .esc_prefix = true,
             .eight_bit = true,
         },
+        .num_lock_modifier = true,
         .bell_is_urgent = conf->bell_is_urgent,
         .tab_stops = tll_init(),
         .wl = wayl,
diff --git a/terminal.h b/terminal.h
index 6a8e340b..5c7a9501 100644
--- a/terminal.h
+++ b/terminal.h
@@ -252,6 +252,7 @@ struct terminal {
         bool eight_bit;
     } meta;
 
+    bool num_lock_modifier;
     bool bell_is_urgent;
 
     /* Saved DECSET modes - we save the SET state */
@@ -275,6 +276,7 @@ struct terminal {
         uint32_t mouse_urxvt:1;
         uint32_t meta_eight_bit:1;
         uint32_t meta_esc_prefix:1;
+        uint32_t num_lock_modifier:1;
         uint32_t bell_is_urgent:1;
         uint32_t alt_screen:1;
     } xtsave;