The 26-year-old former SuperSport defender got his break in Europe with Feyenoord in 2009, but after limited game-time during his four-year stay, where he also spent time on loan with Excelsior, Mokotjo then joined PEC Zwolle for one season before a move to Twente in 2014.
He now joins the Bees on a three-year deal, for an undisclosed fee, subject to international clearance.
Brentford’s Co-Director of Football Rasmus Ankersen revealed his delight at signing the talented South African.
He told the club’s official website: “We have been scouting Kamo for two years and we believe he is a perfect match to our style of play.
“We are really pleased that it was possible to come to an agreement with Twente this summer and especially that we could sign him early in the window.
“It means that he will be able to travel with the rest of the squad to pre-season camp on Saturday to take part in the important preparations for next season.”
Head Coach Dean Smith added: “am pleased that we have been able to add Kamo to our group now he has become available.
“He is a player that we have been looking at for a while and we are sure he will fit into the system and style that we have here.”
“Kamo is a defensive midfielder who can break play up, cover a lot of ground and use the ball intelligently. He is a player that will certainly add to the qualities we already have within the squad.”
Mokotjo captained Twente last season and made 32 Eredivisie starts as the club finished in seventh place.