diff --git a/src/_pytest/capture.py b/src/_pytest/capture.py
index bcfd3449f..6131a46df 100644
--- a/src/_pytest/capture.py
+++ b/src/_pytest/capture.py
@@ -381,7 +381,7 @@ class FDCaptureBinary:
         self.targetfd_save = os.dup(targetfd)
 
         if targetfd == 0:
-            self.tmpfile = open(os.devnull)
+            self.tmpfile = open(os.devnull, encoding="utf-8")
             self.syscapture = SysCapture(targetfd)
         else:
             self.tmpfile = EncodedFile(