Spiro Moisiu was born on 5 May 1900 in Kavajë, to Theodori Moisiu, an educated merchant fluent in several languages, and Ana Stavri. Spiro's father came from the well-known Moisiu family of Kavajë which had roots in the city as far back as the 16th century. He was a close relative of the famous actor Alexander Moissi. Spiro's grandfather Gregor and Aleksandër's grandfather Kostandin were brothers and the sons of Themistokli Moisiu. Theodori was killed in 1913 by the rebels who opposed the Albanian government of Ismail Qemali. This left a young Spiro to be raised by his mother.