Karim Kajymqanuly Massimov (Kazakh: Мәсімов, Кәрім Қажымқанұлы, Russian: Карим Кажимканович Масимов an ethnic Naiman, born in 1965 in Tselinograd, Kazakh SSR, USSR; now Astana, Kazakhstan) has served as Prime Minister in the Government of Kazakhstan since 10 January 2007.

Massimov is fluent in Uyghur, Kazakh, Russian, Chinese, English,and Arabic. He studied in China and worked in Hong Kong where he headed Kazakhstan's trading operations. At the same time, he is thought to be well connected within the Kremlin. He previously served as the Deputy Prime Minister from 19 January 2006 to 9 January 2007 and as Minister of Economy and Budget Planning, Minister of Transport and Communications in 2001. According to Pravda, the public perceives Massimov as "one of the most influential figures in the president's inner circle."

President Nazarbayev nominated Massimov to succeed Daniyal Akhmetov as Prime Minister on 9 January 2007. The Nur Otan party endorsed Massimov's candidacy and Parliament confirmed the nomination on 10 January.