Santander has been a backer of McLaren since 2007 and is also a sponsor of the rival Ferrari Formula One team.
"In such a competitive international sponsorship market, the fact that such a prestigious company has chosen to partner with McLaren Mercedes is a reflection of the strength of our brand," said Ekrem Sami, managing director of McLaren Marketing.
McLaren's former world champion Jenson Button will continue to feature in Santander marketing campaigns.
McLaren had a dismal season last year, failing to finish on the podium in a race for the first time since 1980.
It is yet to find a title sponsor to replace telecoms group Vodafone which pulled out at the end of last season.