The 44-year-old Spaniard, a former winger at Liverpool and Real Mallorca among others, took charge in late January after the club parted ways with Dino Toppmöller. He recorded four wins, five draws and five defeats in his brief tenure. Frankfurt finished eighth, missing out on European qualification and falling well short of the previous season's third-place finish.
Sporting director Markus Krösche confirmed the departure on the club's official website.
"After intensive discussions we jointly came to the decision to end our collaboration with immediate effect. Albert Riera took over the team during a difficult period and dedicated himself to Eintracht Frankfurt with great diligence and commitment.
"Albert and his staff also gave us valuable impulses through their meticulous work, which we expressly want to thank them for. At the same time, after an open and honest analysis of the sporting development, we came to the conclusion that we want to take a different path ahead of the coming season."
Riera himself accepted responsibility for the results while defending the manner in which he approached the role.
"As head coach I take responsibility for the sporting results, and during this entire period my only focus was on improving the team and achieving success. I felt it was my duty to protect the club and the players, and I would act the same way again. Personal interests never played any role for me. My goal was, is and will always be the same: to develop players and achieve success."
His assistants Pablo Remon Arteta and Lorenzo Dolcetti also depart. Sport1 reports that Matthias Jaissle, who won the AFC Champions League with Saudi club Al-Ahli this season, is the leading candidate to replace him.