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Matfield is the all-time record caps holder for the Springboks, collecting 127 since his debut in 2001, and winning the World Cup in 2007.
"This is definitely my swansong. I've got to the end of May," the 38-year-old lock told BBC Radio Northampton.
"Hopefully we can win a trophy or two and then that will be me."
Matfield made his Saints debut against Gloucester last month after joining up with Jim Mallinder's side after the World Cup.
After a poor start to the season, Saints have risen to fifth in the Premiership and top of their European Champions Cup group after two matches.
On Saturday, they travel to a Racing 92 side set to give New Zealand World Cup-winning star Dan Carter a debut, and Matfield empathises with the fly-half.
"I've gone through the same, going to France after winning a World Cup in 2007. A lot of the time it's not that easy just to go in there and run the show.
"Dan Carter would have been used to running the show exactly how he wants to run it at the Crusaders and the All Blacks.
"Now he's into a different system, he has to adapt a little bit, he has to take a bit of theirs and give a bit of input, he's got to learn the language.
"It won't be that easy to step in there to be the Dan Carter we all know, but saying that he's a quality player. If he gets an opportunity and has to make a decision, 90% of the time he'll make the right one."
South Africa legend Victor Matfield hopes to help Northampton Saints win a trophy before retiring at the end of the season.