In Islam, tawhid is the Arabic term for the oneness of God affirmed by the first pillar.
The concept states that God, Allah, is unique, without partners, rivals, equals, or offspring. It is central to the Islamic declaration of faith, the shahada, which affirms that there is no deity but God and that Muhammad is His messenger.
Tawhid is often discussed alongside its opposite, shirk, meaning associating partners with God. Islamic theology and worship are therefore strongly shaped by the idea that prayer, devotion, and ultimate authority belong to God alone. Tawhid is not itself a separate pillar; rather, it expresses the theological foundation behind the shahada, the first pillar of Islam.