The towering central defender has been confirmed at the club for the next three seasons.
Brian Onyango has joined Mamelodi Sundowns on a three-year deal with a two-year option to extend.
“The Kenyan International joins Masandawana as a free agent, he last turned out for Maritzburg United.
“The centre-back comes with a wealth of international and local experience as he has played for Santos, the Team of Choice and his national side. Onyango first moved to South Africa in 2012 to join the now ABC Motsepe based Santos.
“Welcome to Masandawana Brian Onyango!” the club said on their official website.
He featured for Harambee stars in the 2-1 win friendly against Zambia.