In addition to his international experience, Ma'afu will bring to bear the benefit of his time in Super Rugby, where he shone for the Blues in the 2010 competition after proving his class with North Harbour at provincial level.
A powerful, combative performer and confident ball carrier, the 29-year-old is a talented all-round sportsman, having also represented Tonga at tennis and golf.
He is the second major addition to the Warriors squad for 2012/13 to be confirmed to date, with wing/centre Sean Lamont set to make an emotional homecoming. Twelve senior players have also put pen to paper on long-term contract extensions in recent months.
Ma'afu's deal takes him up to the end of May 2014, subject to the appropriate visa being obtained. He currently plays for the Mistubishi club in Japan.
Ma'afu told www.glasgowwarriors.org: "I'm delighted to have signed for a major club like Glasgow Warriors, and can't wait to become part of the team in the summer.
"I know they've been doing well in the RaboDirect PRO12 this season, and it's exciting to know I'll be able to play a part in big games in that competition and the Heineken Cup.
"I've been very impressed by what everyone at the Warriors has told me about where they want to take the club - it's clear that there is a lot of ambition, and a talented squad in place. It's going to be a fantastic place to play my rugby."
Head coach Sean Lineen hailed the signing as a "real coup", saying: "We're all really excited about what Viliami will offer us from next season. He's proved his ability on some of the biggest stages in world rugby, he's got real presence and leadership potential, he's at a great age for a loose forward and he's hungry for success.
"It's a great all-round package to have in a signing, and I'm convinced he'll make a really positive impact. We've got good strength in depth in the back row, and Viliami will bring his own flavour and ability to that. He offers another angle of attack, as well as excellent defensive qualities."
Managing director Nathan Bombrys said: "Signing Viliami is a significant boost for everyone at Glasgow Warriors ahead of another massive match this weekend. We're constantly looking to improve our squad, and Viliami's arrival is a big step in the right direction.
"We're very happy with the signings and re-signings we've made so far, and we'll be working hard to give the Warriors supporters even more good news in the coming weeks and months."
News of Ma'afu's signing is a real pre-match tonic for Glasgow ahead of Saturday's crunch RaboDirect PRO12 clash with table-topping Leinster at Firhill (kick-off 6pm).
Supporters who buy one adult and one under-18 ticket for the game online by midnight on Tuesday will get another under-18 ticket absolutely FREE.
The offer is valid for multiple purchases i.e. if fans buy one adult ticket and two under-18 tickets, they'll get another TWO under-18 tickets absolutely FREE.
See www.glasgowwarriors.org for details and to book.
Adult season ticket holders can also bring an under-18 to the match for FREE, using Voucher B in their season ticket book. To assist with event planning, season ticket holders wishing to take advantage of this offer are requested to email info@glasgowwarriors.org by 12noon on Tuesday.
The support we receive from rugby clubs throughout Glasgow and the west is hugely appreciated by everyone at the Warriors. To say thanks, we're offering every adult who buys a ticket through their own club's website for the Leinster game another FREE adult ticket.
The deadline for this offer is also midnight on Tuesday 21 February.
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