Bhatnagar (भटनागर) is a common surname used mostly in northern India among the Kayastha caste of Hindus.
People with this surname include:
Shanti Swarup Bhatnagar (1894-1955), Indian scientist
Prabhu Lal Bhatnagar (1912 – 1976), Indian mathematician known for Bhatnagar–Gross–Krook operator
V. K. Bhatnagar, founder of Manav Sthali School and Bhatnagar International School
Shivani Bhatnagar (died 1999), Indian Express journalist
Ram Ratan Bhatnagar, Hindi scholar and professor at University of Sagar
Arvind Bhatnagar (1936-2006), Indian astronomer; founder-director of the Udaipur Solar Observatory and the Nehru Planetarium of Bombay
Deepti Bhatnagar, Indian model and actress