Martinez joined Arsenal from Independiente in 2010 and has appeared for both the Argentinian U17 and U20 sides.
The 22-year-old has made eight appearances for the Gunners in total as well as going out on loan to Oxford United, Sheffield Wednesday and Rotherham.
“We are delighted to have brought Emi to the club for the season,” head coach Kenny Jackett told the Wolves official website.
“I have been aware of him from being in and around the Arsenal set-up for a few years and he also has experience of the Championship from loan spells.
“It is very important to have good competition among your goalkeepers not just at the start of the season but as it progresses.
“So it is good to bring Emi in right at the start and we are looking forward to working with him.”
Head of football development and recruitment Kevin Thelwell added: “We are always looking to strengthen the squad and each position as much as we can.
“The opportunity to take Emiliano Martinez, who has played in Arsenal’s first team and been on loan in this division, is one that was too good to turn down.
“It will bring us some strong competition for that number one jersey.”