diff --git a/lib/pure/asyncdispatch.nim b/lib/pure/asyncdispatch.nim
index 70d94b023e..3c0a2257b0 100644
--- a/lib/pure/asyncdispatch.nim
+++ b/lib/pure/asyncdispatch.nim
@@ -269,6 +269,23 @@ proc processPendingCallbacks(p: PDispatcherBase; didSomeWork: var bool) =
     cb()
     didSomeWork = true
 
+proc processTimersBeforePoll(
+  p: PDispatcherBase, didSomeWork: var bool
+): Option[int] {.inline.} =
+  # Do not let an expired timeout overtake completion callbacks which are
+  # already pending. `adjustTimeout` makes the I/O poll non-blocking when the
+  # callback queue is non-empty.
+  if p.callbacks.len == 0:
+    result = processTimers(p, didSomeWork)
+
+proc processCallbacksAndTimers(p: PDispatcherBase; didSomeWork: var bool) =
+  # A completed operation can take multiple queued callbacks to propagate
+  # through its public future. Process the whole chain before expired timers.
+  processPendingCallbacks(p, didSomeWork)
+  discard processTimers(p, didSomeWork)
+  # Timer futures must still propagate within this dispatcher iteration.
+  processPendingCallbacks(p, didSomeWork)
+
 proc adjustTimeout(
   p: PDispatcherBase, pollTimeout: int, nextTimer: Option[int]
 ): int {.inline.} =
@@ -399,7 +416,7 @@ when defined(windows) or defined(nimdoc):
         "No handles or timers registered in dispatcher.")
 
     result = false
-    let nextTimer = processTimers(p, result)
+    let nextTimer = processTimersBeforePoll(p, result)
     let at = adjustTimeout(p, timeout, nextTimer)
     var llTimeout =
       if at == -1: winlean.INFINITE
@@ -450,10 +467,7 @@ when defined(windows) or defined(nimdoc):
           result = false
         else: raiseOSError(errCode)
 
-    # Timer processing.
-    discard processTimers(p, result)
-    # Callback queue processing
-    processPendingCallbacks(p, result)
+    processCallbacksAndTimers(p, result)
 
 
   var acceptEx: WSAPROC_ACCEPTEX
@@ -1404,7 +1418,7 @@ else:
 
     result = false
     var keys: array[64, ReadyKey]
-    let nextTimer = processTimers(p, result)
+    let nextTimer = processTimersBeforePoll(p, result)
     var count =
       p.selector.selectInto(adjustTimeout(p, timeout, nextTimer), keys)
     for i in 0..<count:
@@ -1447,10 +1461,7 @@ else:
         if writeCbListCount > 0: incl(newEvents, Event.Write)
         p.selector.updateHandle(SocketHandle(fd), newEvents)
 
-    # Timer processing.
-    discard processTimers(p, result)
-    # Callback queue processing
-    processPendingCallbacks(p, result)
+    processCallbacksAndTimers(p, result)
 
   proc recv*(socket: AsyncFD, size: int,
              flags = {SocketFlag.SafeDisconn}): owned(Future[string]) =
diff --git a/tests/async/tasyncclosestall.nim b/tests/async/tasyncclosestall.nim
index 05348587c1..ea4865fc79 100644
--- a/tests/async/tasyncclosestall.nim
+++ b/tests/async/tasyncclosestall.nim
@@ -4,6 +4,7 @@ discard """
   exitcode: 0
 """
 import asyncdispatch, asyncnet
+import std/strutils
 
 when defined(windows):
   from winlean import ERROR_NETNAME_DELETED
@@ -14,6 +15,7 @@ else:
 # even when the socket is closed.
 const
   timeout = 2000
+  messagePaddingSize = 64 * 1024
 var port = Port(0)
 
 var sent = 0
@@ -31,10 +33,12 @@ proc isExpectedDisconnectionError(errCode: int32): bool =
     errCode == EBADF or errCode == ECONNRESET or errCode == EPIPE
 
 proc keepSendingTo(c: AsyncSocket) {.async.} =
+  let messagePadding = repeat('x', messagePaddingSize)
   while true:
-    # This write will eventually get stuck because the client is not reading
-    # its messages.
-    let sendFut = c.send("Foobar" & $sent & "\n", flags = {})
+    # Larger writes reach socket backpressure quickly even on slow CI machines.
+    # This write will eventually get stuck because the client is not reading.
+    # Keep the padding after the newline so recvLine does not drain it.
+    let sendFut = c.send("Foobar" & $sent & "\n" & messagePadding, flags = {})
     var sendTimedOut = false
     try:
       # On some platforms (notably macOS ARM64), the kernel may return
diff --git a/tests/async/tasyncdispatchordering.nim b/tests/async/tasyncdispatchordering.nim
new file mode 100644
index 0000000000..5b226bad8a
--- /dev/null
+++ b/tests/async/tasyncdispatchordering.nim
@@ -0,0 +1,32 @@
+discard """
+  action: run
+"""
+
+import asyncdispatch, os
+
+proc wrap(fut: Future[void]): Future[void] =
+  result = newFuture[void]("wrap")
+  let retFuture = result
+  fut.addCallback proc () =
+    if fut.failed:
+      retFuture.fail(fut.error)
+    else:
+      retFuture.complete()
+
+block:
+  let root = newFuture[void]("root")
+  let wrapped = wrap(wrap(wrap(root)))
+  let completedBeforeDeadline = withTimeout(wrapped, 20)
+
+  # Completion has happened at the bottom of the future chain, but its
+  # callbacks cannot propagate until control reaches the dispatcher.
+  root.complete()
+  sleep(40)
+
+  doAssert waitFor(completedBeforeDeadline)
+
+block:
+  var callbackRan = false
+  sleepAsync(0).addCallback proc () = callbackRan = true
+  poll(0)
+  doAssert callbackRan