diff --git a/src/bufio/bufio.go b/src/bufio/bufio.go
index 160bd8adb3..d589701e19 100644
--- a/src/bufio/bufio.go
+++ b/src/bufio/bufio.go
@@ -133,9 +133,10 @@ func (b *Reader) readErr() error {
 }
 
 // Peek returns the next n bytes without advancing the reader. The bytes stop
-// being valid at the next read call. If Peek returns fewer than n bytes, it
-// also returns an error explaining why the read is short. The error is
-// [ErrBufferFull] if n is larger than b's buffer size.
+// being valid at the next read call. If necessary, Peek will read more bytes
+// into the buffer in order to make n bytes available. If Peek returns fewer
+// than n bytes, it also returns an error explaining why the read is short.
+// The error is [ErrBufferFull] if n is larger than b's buffer size.
 //
 // Calling Peek prevents a [Reader.UnreadByte] or [Reader.UnreadRune] call from succeeding
 // until the next read operation.