The Protestant Church in Western Indonesia Immanuel Semarang, better known as Blenduk Church, is a Protestant church in Semarang, Central Java, Indonesia. Built in 1753, it is the oldest church in the province.

Protestantism is one of the six approved religions in Indonesia, the others being Islam, Roman Catholicism, Hinduism, Buddhism, and Confucianism. It constitutes the bulk of Christianity in Indonesia, which is the second largest religion in the country after Islam.