Sikhism recognizes ten human Gurus before the Guru Granth Sahib became the eternal Guru.
The line of human Gurus begins with Guru Nanak, the founder of Sikhism, and ends with Guru Gobind Singh. Each Guru contributed to the development of Sikh teachings, institutions, scripture, and community identity. The Gurus are traditionally understood as carrying forward the same spiritual light rather than establishing separate, competing doctrines.
At Nanded in 1708, Guru Gobind Singh transferred the spiritual authority of the succession to the Guru Granth Sahib. Sikh tradition therefore treats the scripture as the continuing, eternal Guru rather than recognizing a further human officeholder.
A common mix-up is to count the Guru Granth Sahib as an eleventh human Guru. It is the eternal Guru in Sikhism, but it is not a human Guru. The ten human Gurus span the period from the late fifteenth century to the early eighteenth century.