Naiyaravoro, who tops 125kg, will leave Super Rugby team New South Wales Waratahs later this year, and will arrive at Saints in time to play alongside former Tahs teammate Rob Horne for the 2018-19 Aviva Premiership campaign.
The 26-year-old Fiji-born winger has won two caps for Australia, and scored nine tries in 22 appearances for Glasgow Warriors during the 2015-16 European season.
"Taqele is an immense talent and we feel that he can really fulfil his sizeable potential at Saints," Northampton technical coaching consultant Alan Gaffney said.
"He clearly boasts the physical attributes to cause teams a lot of problems in the Aviva Premiership and in Europe and he showed that during his time with Glasgow.
"Taqele already has a relationship with Rob Horne having played with him at the Waratahs and I'm sure he will make a massive impact."