diff --git a/lib/smalltalk/eval.sx b/lib/smalltalk/eval.sx
index 89f09383..56d69500 100644
--- a/lib/smalltalk/eval.sx
+++ b/lib/smalltalk/eval.sx
@@ -446,27 +446,29 @@
                 temps)
               (st-eval-seq body frame))))))))
 
+;; whileTrue: / whileTrue / whileFalse: / whileFalse — the receiver is the
+;; condition block; the optional argument is the body block. Per ANSI / Pharo
+;; convention, the loop returns nil regardless of how many iterations ran.
 (define
   st-block-while
   (fn
     (cond-block body-block target)
-    (let ((last nil))
-      (begin
-        (define
-          wh-loop
-          (fn
-            ()
-            (let
-              ((c (st-block-apply cond-block (list))))
-              (when
-                (= c target)
-                (begin
-                  (cond
-                    ((not (= body-block nil))
-                      (set! last (st-block-apply body-block (list)))))
-                  (wh-loop))))))
-        (wh-loop)
-        last))))
+    (begin
+      (define
+        wh-loop
+        (fn
+          ()
+          (let
+            ((c (st-block-apply cond-block (list))))
+            (when
+              (= c target)
+              (begin
+                (cond
+                  ((not (= body-block nil))
+                    (st-block-apply body-block (list))))
+                (wh-loop))))))
+      (wh-loop)
+      nil)))
 
 ;; ── Primitive method table for native receivers ────────────────────────
 ;; Returns the result, or the sentinel :unhandled if no primitive matches —
diff --git a/lib/smalltalk/tests/while.sx b/lib/smalltalk/tests/while.sx
new file mode 100644
index 00000000..4d5d244b
--- /dev/null
+++ b/lib/smalltalk/tests/while.sx
@@ -0,0 +1,145 @@
+;; whileTrue: / whileTrue / whileFalse: / whileFalse tests.
+;;
+;; In Smalltalk these are *ordinary* messages sent to the condition block.
+;; No special-form magic — just block sends. The runtime can intrinsify
+;; them later in the JIT (Tier 1 of bytecode expansion) but the spec-level
+;; semantics are what's pinned here.
+
+(set! st-test-pass 0)
+(set! st-test-fail 0)
+(set! st-test-fails (list))
+
+(st-bootstrap-classes!)
+(define ev (fn (src) (smalltalk-eval src)))
+(define evp (fn (src) (smalltalk-eval-program src)))
+
+;; ── 1. whileTrue: with body — basic counter ──
+(st-test
+  "whileTrue: counts down"
+  (evp "| n | n := 5. [n > 0] whileTrue: [n := n - 1]. ^ n")
+  0)
+
+(st-test
+  "whileTrue: returns nil"
+  (evp "| n | n := 3. ^ [n > 0] whileTrue: [n := n - 1]")
+  nil)
+
+(st-test
+  "whileTrue: zero iterations is fine"
+  (evp "| n | n := 0. [n > 0] whileTrue: [n := n + 1]. ^ n")
+  0)
+
+;; ── 2. whileFalse: with body ──
+(st-test
+  "whileFalse: counts down (cond becomes true)"
+  (evp "| n | n := 5. [n <= 0] whileFalse: [n := n - 1]. ^ n")
+  0)
+
+(st-test
+  "whileFalse: returns nil"
+  (evp "| n | n := 3. ^ [n <= 0] whileFalse: [n := n - 1]")
+  nil)
+
+;; ── 3. whileTrue (no arg) — body-less side-effect loop ──
+(st-test
+  "whileTrue without argument runs cond-only loop"
+  (evp
+    "| n decrement |
+     n := 5.
+     decrement := [n := n - 1. n > 0].
+     decrement whileTrue.
+     ^ n")
+  0)
+
+;; ── 4. whileFalse (no arg) ──
+(st-test
+  "whileFalse without argument"
+  (evp
+    "| n inc |
+     n := 0.
+     inc := [n := n + 1. n >= 3].
+     inc whileFalse.
+     ^ n")
+  3)
+
+;; ── 5. Cond block evaluated each iteration (not cached) ──
+(st-test
+  "whileTrue: re-evaluates cond on every iter"
+  (evp
+    "| n stop |
+     n := 0. stop := false.
+     [stop] whileFalse: [
+       n := n + 1.
+       n >= 4 ifTrue: [stop := true]].
+     ^ n")
+  4)
+
+;; ── 6. Body block sees outer locals ──
+(st-test
+  "whileTrue: body reads + writes captured locals"
+  (evp
+    "| acc i |
+     acc := 0. i := 1.
+     [i <= 10] whileTrue: [acc := acc + i. i := i + 1].
+     ^ acc")
+  55)
+
+;; ── 7. Nested while loops ──
+(st-test
+  "nested whileTrue: produces flat sum"
+  (evp
+    "| total i j |
+     total := 0. i := 0.
+     [i < 3] whileTrue: [
+       j := 0.
+       [j < 4] whileTrue: [total := total + 1. j := j + 1].
+       i := i + 1].
+     ^ total")
+  12)
+
+;; ── 8. ^ inside whileTrue: short-circuits the surrounding method ──
+(st-class-define! "WhileEscape" "Object" (list))
+(st-class-add-method! "WhileEscape" "firstOver:in:"
+  (st-parse-method
+    "firstOver: limit in: arr
+       | i |
+       i := 1.
+       [i <= arr size] whileTrue: [
+         (arr at: i) > limit ifTrue: [^ arr at: i].
+         i := i + 1].
+       ^ nil"))
+
+(st-test
+  "early ^ from whileTrue: body"
+  (evp "^ WhileEscape new firstOver: 5 in: #(1 3 5 7 9)")
+  7)
+
+(st-test
+  "whileTrue: completes when nothing matches"
+  (evp "^ WhileEscape new firstOver: 100 in: #(1 2 3)")
+  nil)
+
+;; ── 9. whileTrue: invocations independent across calls ──
+(st-class-define! "Counter2" "Object" (list "n"))
+(st-class-add-method! "Counter2" "init"
+  (st-parse-method "init n := 0. ^ self"))
+(st-class-add-method! "Counter2" "n"
+  (st-parse-method "n ^ n"))
+(st-class-add-method! "Counter2" "tick:"
+  (st-parse-method "tick: count [count > 0] whileTrue: [n := n + 1. count := count - 1]. ^ self"))
+
+(st-test
+  "instance state survives whileTrue: invocations"
+  (evp
+    "| c | c := Counter2 new init.
+     c tick: 3. c tick: 4.
+     ^ c n")
+  7)
+
+;; ── 10. Timing: whileTrue: on a never-true cond runs zero times ──
+(st-test
+  "whileTrue: with always-false cond"
+  (evp "| ran | ran := false. [false] whileTrue: [ran := true]. ^ ran")
+  false)
+
+(list st-test-pass st-test-fail)
diff --git a/plans/smalltalk-on-sx.md b/plans/smalltalk-on-sx.md
index 5a0021a6..06a3a16e 100644
--- a/plans/smalltalk-on-sx.md
+++ b/plans/smalltalk-on-sx.md
@@ -67,7 +67,7 @@ Core mapping:
 - [x] Method invocation captures a `^k` (the return continuation) and binds it as the block's escape. `st-invoke` wraps body in `(call/cc (fn (k) ...))`; the frame's `:return-k` is set to k. Block creation copies `(get frame :return-k)` onto the block. Block invocation sets the new frame's `:return-k` to the block's saved one — so non-local return reaches *back through* any number of intermediate block invocations.
 - [x] `^expr` from inside a block invokes that captured `^k`. The "return" AST type evaluates the expression then calls `(k v)` on the frame's :return-k. Verified: `detect:in:` style early-exit, multi-level nested blocks, ^ from inside `to:do:`/`whileTrue:`, ^ from a block passed to a *different* method (Caller→Helper) returns from Caller.
 - [x] `BlockContext>>value`, `value:`, `value:value:`, `value:value:value:`, `value:value:value:value:`, `valueWithArguments:`. Implemented in `st-block-dispatch` + `st-block-apply` (eval iteration); pinned by 19 dedicated tests in `lib/smalltalk/tests/blocks.sx` covering arity through 4, valueWithArguments: with empty/non-empty arg arrays, closures over outer locals (read + mutate + later-mutation re-read), nested blocks, blocks as method arguments, `numArgs`, and `class`.
-- [ ] `whileTrue:` / `whileTrue` / `whileFalse:` / `whileFalse` as ordinary block sends — runtime intrinsifies the loop in the bytecode JIT
+- [x] `whileTrue:` / `whileTrue` / `whileFalse:` / `whileFalse` as ordinary block sends. `st-block-while` re-evaluates the receiver cond each iteration; with-arg form runs body each iteration; without-arg form is a side-effect loop. Now returns `nil` per ANSI/Pharo. JIT intrinsification is a future Tier-1 optimization (already covered by the bytecode-expansion infra in MEMORY.md). 14 dedicated while-loop tests including 0-iteration, body-less variants, nested loops, captured locals (read + write), `^` short-circuit through the loop, and instance-state preservation across calls.
 - [ ] `ifTrue:` / `ifFalse:` / `ifTrue:ifFalse:` as block sends, similarly intrinsified
 - [ ] Escape past returned-from method raises `BlockContext>>cannotReturn:`
 - [ ] Classic programs in `lib/smalltalk/tests/programs/`:
@@ -108,6 +108,7 @@ Core mapping:
 
 _Newest first. Agent appends on every commit._
 
+- 2026-04-25: `whileTrue:` / `whileFalse:` / no-arg variants pinned (`lib/smalltalk/tests/while.sx`, 14 tests). `st-block-while` returns nil per ANSI; behaviour verified under captured locals, nesting, early `^`, and zero/many iterations. 334/334 total.
 - 2026-04-25: BlockContext value family pinned (`lib/smalltalk/tests/blocks.sx`, 19 tests). Each value/valueN/valueWithArguments: variant verified plus closure semantics (read, write, later-mutation re-read), nested blocks, and block-as-arg. 320/320 total.
 - 2026-04-25: **THE SHOWCASE** — non-local return via captured method-return continuations + 14 NLR tests (`lib/smalltalk/tests/nlr.sx`). `st-invoke` wraps body in `call/cc`; blocks copy creating method's `^k`; `^expr` invokes that k. Verified across nested blocks, `to:do:` / `whileTrue:`, blocks passed to different methods (Caller→Helper escapes back to Caller), inner-vs-outer method nesting. Sentinel-based return removed. 301/301 total.
 - 2026-04-25: `super` send + 9 tests (`lib/smalltalk/tests/super.sx`). `st-super-send` walks from defining-class's superclass; class-side aware; primitives → DNU fallback. Also fixed top-level `| temps |` parsing in `st-parse` (the absence of which was silently aborting earlier eval/dnu tests — counts go from 274 → 287, with previously-skipped tests now actually running).