Assistant coach Azhar Mahmood is to leave Surrey with immediate effect to take up a role with the Pakistan men's team.
The former all-rounder joined the county in 2022 and has helped the club win back-to-back County Championship titles in the last two years.
Mahmood has also had two spells with Surrey. He said it was a "difficult decision" to leave his "second home".
Mahmood was previously Pakistan's assistant coach from 2016 to 2019.
For the T20 series against New Zealand, he will act as interim head coach.
Surrey said they would not be looking for a replacement for Mahmood at this stage.