Shiv Sena (Devanāgarī: शिव सेना Śīv Senā), meaning Army of Shiva, referring to Shivaji, is a Hindu nationalist, militant nativist political party in India founded on June 19, 1966 by Bal Thackeray, who is currently the chief of the party his son Uddhav Thackeray is president. The Sena's ideology is based on the concepts of 'Bhumiputra' (Marathi for "Sons of the Soil") and Hindutva or Hindu nationalism. The 'Bhumiputra' ideology refers to the Shiv Sena's belief that Maharashtrians (Marathi People) are superior in race and culture to the ones of rest of India, and that they deserve more rights in Maharashtra than those who are not from Maharashtra. However, in recent times, the Sena has laid more emphasis on Hindutva. In the 13th Lok Sabha (1999-2004), it had 15 (out of 545) members. During that period, the party was part of the National Democratic Alliance, which ruled at the national level. Manohar Joshi, a Shiv Sainik, was the Speaker of Lok Sabha 2002-2004. The Shiv Sena also ruled the Maharashtra state in its past and is one of the most influential Hindutva parties in the region.

Bharatiya Kamgar Sena ("Indian Worker's Army"), a labour union, is affiliated to the Shiv Sena. The Akhil Bharatiya Vidyarthi Sena ("All India Students' Army") is the student wing of Shiv Sena.