Sergei Filin lost much of his sight as a result of the January 2012 attack.
Pavel Dmitrichenko, a Bolshoi soloist, was convicted in December of organizing the attack and sentenced to six years in prison. The Moscow City Court on Thursday reduced his sentence by six months to 5 1/2 years.
The sentence for Yuri Zarutsky, who splashed the acid in Filin's face, was cut to nine years instead of 10, while his driver, Andrei Lipatov, had his four-year sentence cut in half to two years.
Convicts in Russia can apply for parole after serving half of their sentences, but their appeals can be denied for a variety of reasons.
All three convicted in the Bolshoi attack were arrested in March 2013, so they already have served the first year of their sentences.
The trial often focused less on the defendants' roles in the crime than on Filin's management of the ballet company, where infighting has raged for years. As part of his defense, Dmitrichenko cited several incidents in which dancers were driven to tears by the artistic director.
Dmitrichenko testified that he had never intended for Filin to be so seriously injured, but said he accepted "moral responsibility" for the attack.