diff --git a/sorts/sleep_sort.py b/sorts/sleep_sort.py
new file mode 100644
index 000000000000..8387f9718b1c
--- /dev/null
+++ b/sorts/sleep_sort.py
@@ -0,0 +1,83 @@
+from typing import List
+import threading
+import time
+
+
+def sleep_sort(numbers: List[int], simulate: bool = True, scale: float = 0.01) -> None:
+    """
+    Perform Sleep Sort on the given list of integers.
+
+    Sorts the list numbers in place using the Sleep Sort algorithm.
+
+    Behavior:
+    - Destructive: modifies the list numbers.
+    - Only accepts integers (positive, zero, or negative).
+    - Default simulate=True runs instantly by simulating timed wake-ups (safe for tests/CI).
+    - If simulate=False, the function spawns one thread per element and uses time.sleep;
+      this mode causes real waiting time proportional to element values.
+    - scale (seconds per unit) applies only when simulate=False.
+
+    Examples
+    --------
+    >>> nums = [3, 1, 2]
+    >>> sleep_sort(nums)
+    >>> nums
+    [1, 2, 3]
+
+    >>> nums = [0, 0, 1]
+    >>> sleep_sort(nums)
+    >>> nums
+    [0, 0, 1]
+
+    >>> nums = [-2, 1, 0]
+    >>> sleep_sort(nums)
+    >>> nums
+    [-2, 0, 1]
+
+    >>> sleep_sort([1.5, 2])
+    Traceback (most recent call last):
+    ...
+    TypeError: integers only please
+    """
+    if not numbers:
+        return
+
+    if any(not isinstance(x, int) for x in numbers):
+        raise TypeError("integers only please")
+
+    min_val = min(numbers)
+    offset = -min_val if min_val < 0 else 0
+
+    if simulate:
+        # Simulated wake-up: bucket by wake time (value + offset), preserve order
+        buckets = {}
+        for idx, val in enumerate(numbers):
+            wake = val + offset
+            buckets.setdefault(wake, []).append((idx, val))
+        result: List[int] = []
+        for wake in sorted(buckets.keys()):
+            for _, val in buckets[wake]:
+                result.append(val)
+        numbers[:] = result
+        return
+
+    # Real threaded mode: causes actual delays proportional to element values
+    results: List[int] = []
+    lock = threading.Lock()
+
+    def worker(value: int) -> None:
+        time.sleep((value + offset) * scale)
+        with lock:
+            results.append(value)
+
+    threads: List[threading.Thread] = []
+    for val in numbers:
+        t = threading.Thread(target=worker, args=(val,))
+        t.daemon = True
+        t.start()
+        threads.append(t)
+
+    for t in threads:
+        t.join()
+
+    numbers[:] = results