diff --git a/lib/hyperscript/compiler.sx b/lib/hyperscript/compiler.sx
index f00d6fef..e34fa5e0 100644
--- a/lib/hyperscript/compiler.sx
+++ b/lib/hyperscript/compiler.sx
@@ -1426,6 +1426,20 @@
                     (quote hs-toggle-class!)
                     (hs-to-sx (nth ast 2))
                     (nth ast 1))))
+              ((= head (quote toggle-class-until))
+                (let
+                  ((cls (nth ast 1))
+                    (tgt (hs-to-sx (nth ast 2)))
+                    (event-name (nth ast 3))
+                    (source (nth ast 4)))
+                  (list
+                    (quote do)
+                    (list (quote hs-toggle-class!) tgt cls)
+                    (list
+                      (quote hs-wait-for)
+                      (if source (hs-to-sx source) (quote me))
+                      event-name)
+                    (list (quote hs-toggle-class!) tgt cls))))
               ((= head (quote set-on))
                 (list
                   (quote hs-set-on!)
diff --git a/lib/hyperscript/parser.sx b/lib/hyperscript/parser.sx
index 233eb9b7..aba0bf5d 100644
--- a/lib/hyperscript/parser.sx
+++ b/lib/hyperscript/parser.sx
@@ -1132,14 +1132,45 @@
             ((= (tp-type) "class")
               (let
                 ((cls (do (let ((v (tp-val))) (adv!) v))))
+                (define
+                  collect-classes
+                  (fn
+                    (acc)
+                    (if
+                      (= (tp-type) "class")
+                      (let
+                        ((v (tp-val)))
+                        (adv!)
+                        (collect-classes (append acc (list v))))
+                      acc)))
                 (let
-                  ((tgt (parse-tgt-kw "on" (list (quote me)))))
-                  (if
-                    (match-kw "for")
-                    (let
-                      ((dur (parse-expr)))
-                      (list (quote toggle-class-for) cls tgt dur))
-                    (list (quote toggle-class) cls tgt)))))
+                  ((extra-classes (collect-classes (list))))
+                  (let
+                    ((tgt (parse-tgt-kw "on" (list (quote me)))))
+                    (cond
+                      ((> (len extra-classes) 0)
+                        (list
+                          (quote toggle-between)
+                          cls
+                          (first extra-classes)
+                          tgt))
+                      ((match-kw "for")
+                        (let
+                          ((dur (parse-expr)))
+                          (list (quote toggle-class-for) cls tgt dur)))
+                      ((match-kw "until")
+                        (let
+                          ((event-name (tp-val)))
+                          (adv!)
+                          (let
+                            ((source (if (match-kw "from") (parse-expr) nil)))
+                            (list
+                              (quote toggle-class-until)
+                              cls
+                              tgt
+                              event-name
+                              source))))
+                      (true (list (quote toggle-class) cls tgt)))))))
             ((= (tp-type) "style")
               (let
                 ((prop (get (adv!) "value")))
diff --git a/shared/static/wasm/sx/hs-compiler.sx b/shared/static/wasm/sx/hs-compiler.sx
index f00d6fef..e34fa5e0 100644
--- a/shared/static/wasm/sx/hs-compiler.sx
+++ b/shared/static/wasm/sx/hs-compiler.sx
@@ -1426,6 +1426,20 @@
                     (quote hs-toggle-class!)
                     (hs-to-sx (nth ast 2))
                     (nth ast 1))))
+              ((= head (quote toggle-class-until))
+                (let
+                  ((cls (nth ast 1))
+                    (tgt (hs-to-sx (nth ast 2)))
+                    (event-name (nth ast 3))
+                    (source (nth ast 4)))
+                  (list
+                    (quote do)
+                    (list (quote hs-toggle-class!) tgt cls)
+                    (list
+                      (quote hs-wait-for)
+                      (if source (hs-to-sx source) (quote me))
+                      event-name)
+                    (list (quote hs-toggle-class!) tgt cls))))
               ((= head (quote set-on))
                 (list
                   (quote hs-set-on!)
diff --git a/shared/static/wasm/sx/hs-parser.sx b/shared/static/wasm/sx/hs-parser.sx
index 30523f26..aba0bf5d 100644
--- a/shared/static/wasm/sx/hs-parser.sx
+++ b/shared/static/wasm/sx/hs-parser.sx
@@ -1132,14 +1132,45 @@
             ((= (tp-type) "class")
               (let
                 ((cls (do (let ((v (tp-val))) (adv!) v))))
+                (define
+                  collect-classes
+                  (fn
+                    (acc)
+                    (if
+                      (= (tp-type) "class")
+                      (let
+                        ((v (tp-val)))
+                        (adv!)
+                        (collect-classes (append acc (list v))))
+                      acc)))
                 (let
-                  ((tgt (parse-tgt-kw "on" (list (quote me)))))
-                  (if
-                    (match-kw "for")
-                    (let
-                      ((dur (parse-expr)))
-                      (list (quote toggle-class-for) cls tgt dur))
-                    (list (quote toggle-class) cls tgt)))))
+                  ((extra-classes (collect-classes (list))))
+                  (let
+                    ((tgt (parse-tgt-kw "on" (list (quote me)))))
+                    (cond
+                      ((> (len extra-classes) 0)
+                        (list
+                          (quote toggle-between)
+                          cls
+                          (first extra-classes)
+                          tgt))
+                      ((match-kw "for")
+                        (let
+                          ((dur (parse-expr)))
+                          (list (quote toggle-class-for) cls tgt dur)))
+                      ((match-kw "until")
+                        (let
+                          ((event-name (tp-val)))
+                          (adv!)
+                          (let
+                            ((source (if (match-kw "from") (parse-expr) nil)))
+                            (list
+                              (quote toggle-class-until)
+                              cls
+                              tgt
+                              event-name
+                              source))))
+                      (true (list (quote toggle-class) cls tgt)))))))
             ((= (tp-type) "style")
               (let
                 ((prop (get (adv!) "value")))
@@ -2472,14 +2503,6 @@
                   (let
                     ((acc2 (append acc (list cmd))))
                     (cond
-                      ((match-kw "unless")
-                        (let
-                          ((cnd (parse-expr)))
-                          (cl-collect
-                            (append
-                              acc
-                              (list
-                                (list (quote if) (list (quote no) cnd) cmd))))))
                       ((match-kw "then")
                         (cl-collect (append acc2 (list (quote __then__)))))
                       ((and (not (at-end?)) (= (tp-type) "keyword") (cmd-kw? (tp-val)))