diff --git a/Lib/_pyrepl/reader.py b/Lib/_pyrepl/reader.py
index 0ebd9162eca4bb..6536b9316c1e59 100644
--- a/Lib/_pyrepl/reader.py
+++ b/Lib/_pyrepl/reader.py
@@ -28,12 +28,13 @@
 from dataclasses import dataclass, field, fields
 
 from . import commands, console, input
-from .utils import wlen, unbracket, disp_str, gen_colors, THEME
+from .utils import wlen, unbracket, disp_str, gen_colors, ColorSpan, THEME
 from .trace import trace
 
 
 # types
 Command = commands.Command
+from collections.abc import Callable, Iterator
 from .types import Callback, SimpleContextManager, KeySpec, CommandName
 
 
@@ -213,6 +214,7 @@ class Reader:
     lxy: tuple[int, int] = field(init=False)
     scheduled_commands: list[str] = field(default_factory=list)
     can_colorize: bool = False
+    gen_colors: Callable[[str], Iterator[ColorSpan]] = field(default=gen_colors)
     threading_hook: Callback | None = None
 
     ## cached metadata to speed up screen refreshes
@@ -312,7 +314,7 @@ def calc_screen(self) -> list[str]:
         prompt_from_cache = (offset and self.buffer[offset - 1] != "\n")
 
         if self.can_colorize:
-            colors = list(gen_colors(self.get_unicode()))
+            colors = list(self.gen_colors(self.get_unicode()))
         else:
             colors = None
         trace("colors = {colors}", colors=colors)
diff --git a/Misc/NEWS.d/next/Library/2025-11-16-08-45-48.gh-issue-139167.Yr43k1.rst b/Misc/NEWS.d/next/Library/2025-11-16-08-45-48.gh-issue-139167.Yr43k1.rst
new file mode 100644
index 00000000000000..35a471f9b3bffb
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-11-16-08-45-48.gh-issue-139167.Yr43k1.rst
@@ -0,0 +1 @@
+Allow users to use customized ``gen_colors`` function for pyrepl ``Reader``.