The American former Formula 1 driver was left without a seat at the end of 2010 after he was released by Red Bull Racing following two full seasons in NASCAR's top series.
Speed will join the Max Q Motorsports team to drive a Ford Fusion from this weekend's race in Indianapolis.
"I am excited to get back to the track," said Speed. "Max Q Motorsports seem to have a good operation and a great group of guys working on the 37.
"Ford has a great engine package so I'm hopeful that we can get the ball rolling quickly and be competitive out the gate."
The #37 car Speed will drive is currently in 39th place in the Sprint Cup owner points, which means the American will have to qualify on time this weekend.
"We are excited to have Scott Speed join us," said Larry Gunselman, Max Q Motorsports owner.
"He has shown great talent in a small period of time in stock cars and with the right operation I think things can really take off. We will start by focusing on qualifying and go from there."
