Batsman Finch returns for a second season at Headingley and will be available for all formats from the end of his Indian Premier League commitments, while all-rounder Maxwell will feature in the NatWest T20 Blast.
Finch made an LV= County Championship century against Warwickshire last summer and averaged 48.50 as the Tykes won the four-day competition.
He also made two Twenty20 half-centuries, including a superb 89 against Nottinghamshire.
“It is great to be heading back to Yorkshire,” said Finch. “I enjoyed my time with the club last year and made some lifelong friendships.
“This year the club will be aiming to win the title again and there is a major emphasis on doing well in the T20 competition. Having Maxi playing alongside me will be terrific. He is a true competitor and loves the shorter form of the game.”
Maxwell, Australia’s newly-crowned Twenty20 player of the year, has previously played for Hampshire and Surrey.
He said: “I’m pumped and can’t wait to play for Yorkshire in the T20 Blast competition.
“Yorkshire are one of biggest clubs in the world and to get the chance to play for them is an honour. I had two great spells with Hampshire and loved every minute. Heading to Yorkshire gives me a new challenge that I will relish.”
First-team coach Jason Gillespie added: “We’re absolutely thrilled to bits to be able to secure the services of two very exciting players in world cricket.”