Kalmukhambet Nurmukhanbetuly Kassymov (Kazakh: Қалмұханбет Нұрмұханбетұлы Қасымов, Qalmūhanbet Nūrmūhanbetūly Qasymov; born 18 May 1957) is a Kazakh politician who served as the head of the State Security Service from January 2020 until his dismissal in July 2021, likely due to the scandals revolving the Pegasus Project.

Prior to that, Kassymov was the secretary of Security Council of Kazakhstan from February 2019 to January 2020 and the Minister of Internal Affairs from 2011 to 2019.

In 1988, he became the deputy head of the Public Order Protection Department of the Internal Affairs Directorate of the Almaty Region.

From March to July 1997, he served as the head of the Criminal Police Department of the Ministry of Internal Affairs of Kazakhstan.

He served that position until he became the head of the Department of Internal Affairs of the East Kazakhstan Region in September 2009.