K. K. Mahajan (2 October 1944 – 13 July 2007) was a noted Indian cinematographer. He won four National Film Awards for Best Cinematography for Basu Chatterjee's Sara Akash (1970), Mani Kaul's Uski Roti (1971), Kumar Shahani's Maya Darpan (1973) and Mrinal Sen's Chorus (1974). He is best known for his work with Kumar Shahani, Mani Kaul and Basu Chatterjee's early films and his extensive work with Mrinal Sen.
Starting in the late 1960s, he worked simultaneously with parallel and mainstream films for the next four decades. In all he shot 84 feature films, around 100 commercials and over 20 noted documentaries and several television serials. He got the chance to work with prominent film directors like Mrinal Sen, Mani Kaul, Kumar Shahani, Basu Chatterjee, Ramesh Sippy, Subhash Ghai and Mohan Kumar.
Born in Gurdaspur in Punjab, Mahajan graduated in a physics from Panjab University, Chandigarh. Thereafter he joined Film and Television Institute of India (FTII), and graduating in Motion Picture Photography in 1966, with a gold medal.