The Orbeli brothers were born in a noble family of intellectuals. Their father, Abgar Orbeli (1849-1912), had graduated from the Petersburg University, faculty of Law. He was an educated person and possessed a huge and affluent library. The Orbeli's mother, Varvara Movses Arghoutyan (1857-1937), descended from a duke family and had graduated from Tiflis female gymnasium.

The elder son of Abgar Orbeli, Rouben (1880-1943), followed his father’s footsteps and also graduated from Petersburg University, faculty of Law. Before the October Revolution he used to work in Senate in the capacity of Secretary of Appeal Committee. But later on he abandoned jurisprudence and indulged in submarine archeology, making his aim to investigate the cultural values lying in the seabed. The middle brother, Levon Orbeli (1982-1958), was born in Tsakhkadzor. He graduated form Petersburg Army Medical College.

He was the disciple of famous Russian physiologist Pavlov. The discovery of cerebrum and the new regularities of its controlling effect activities are connected with his name. In 1942 he was elected Vice President of the Academy of Sciences of USSR; later on he was appointed Head of Army Medical College. Levon Orbeli was a factual member of both the Academy of Sciences of USSR and ASSR.

The younger son of Abgar Orbeli, Hovsep Orbeli (1887-1961), graduated from the Historical-Philological faculty of Petersburg University and was the follower of famous specialist of Eastern and Armenian Studies Nikoghayos Mar. Hovsep Orbeli is recognized as a considerable specialist of Eastern and Armenian Studies, eminent representative of scientific world, Director of Leningrad's Hermitage Gallery and the first president of the Academy of Sciences of ASSR.