Sikhism is based on the spiritual teachings of Guru Nanak (the first Guru), and the ten successive Sikh gurus. With over 25 million adherents worldwide, Sikhism is a minor Indian religion spread out around the world.A Sikh is a disciple of the Guru.ikhism (/ˈsɪkɨzəm/ ; Sikkhī, [ˈsɪkːʰiː]), or Sikhi (from Sikh, meaning a disciple, or a learner), is a monotheistic religion that originated in South Asia during the 15th century.