Matthew and Grace Huang of Los Angeles were originally jailed on murder charges following the January 2013 death of their adopted daughter Gloria.
They were released from prison last November, but banned from leaving during the trial.
In March, the court sentenced them to three years in prison for child endangerment.
The Huangs, of Asian descent, have remained out of prison during their appeal.
They have insisted that their daughter, who was born in Ghana, died of medical problems complicated by unusual eating habits.
The couple has two other African-born adopted children who left Qatar during the trial to live with relatives in the United States. Washington has urged its Gulf ally to lift their travel ban.
The couple met with US Ambassador to Qatar Dana Shell Smith yesterday.
The prosecution alleged that the couple had denied food to Gloria and said the child was locked in her room at night.
The girl was pronounced dead when the Huangs took her to the hospital in January 2013.
An investigative report by the Qatari police had focused partially on why the Huangs would adopt children who did not share their "hereditary traits", according to the family's website.
The Huangs will be able to take their case to a higher court after the appeals verdict, though Qatar's highest judicial body traditionally rules in favor of the lower court's rulings.
