The ex-Springbok returned to Cape Town after appearing for the Barbarians in recent weeks and he since has made the tough decision to make the move home permanently.
Wentzel leaves the UK after six years of excellent service to Premiership Rugby with Leicester Tigers, Leeds Carnegie and London Wasps.
In his two seasons as a Wasps player he made 51 appearances and regularly captained the side, while overall he has played 114 games in the Premiership.
He said: “It has not been easy for me to make this decision but I left South Africa nine years ago and I realise that is where I need to be now around my family. It is tough to leave Wasps when things are looking so bright and I am grateful to Dai Young for understanding my position. On the other hand I am happy to be leaving when things are going well for the Club and I think there is a very positive future with the squad that Dai is developing here. I was lucky enough to captain Wasps a number of times over the past few years and I want to thank all of the fans for getting behind us during some rocky times. I have really enjoyed playing in the Premiership and hopefully there are a few more years in my body yet but I haven’t got any fixed plans for playing when I return home.”
London Wasps Director of Rugby Dai Young added: “It’s disappointing to lose Marco, especially at this time of year which will make replacing him very difficult. He has played an important role for the Club over the last two seasons and I know it wasn’t an easy decision for him. He goes with us wishing him all the best in the future.”