Ryan Alebiosu will link-up with the Scottish club for the upcoming campaign as he looks to get more first-team minutes under his belt.
The 20-year-old is yet to make a competitive appearance for the Gunners, and spent last season on loan at League One's Crewe Alexandra.
Alebiosu made six appearances for the Railwaymen who finished bottom of the division and were sent down to League Two.
In Kilmarnock, Alebiosu joins a side which finished top of the Scottish Championship last season, and subsequently earned promotion to the top tier.
Killie boss Derek McInnes said: "He's a young man but what he lacks in experience in terms of game time he makes up for with endeavour, running power and athleticism.
"He's a good size, we feel he will give us good options on that right-and side, he can play right back, right wing back and right of a three if needed.
"While he is young we are keen for him to come here and make an impression."
Over the last three years, the bulk of Alebiosu's football has been played for Arsenal U23s. The defender has made 29 appearances for the team since 2019, and scored one goal in the process.