The Tokyo High Court has found three former power company executives not guilty of professional negligence.
The decision is the latest in the only criminal prosecution stemming from Japan's 2011 nuclear disaster.
It follows an acquittal by the Tokyo District Court in 2019.
Three reactors at the Fukushima Daiichi nuclear power plant melted down following the earthquake and tsunami. Patients at a hospital in the prefecture and others died during the ensuing evacuations.
The former executives were accused of being responsible for 44 of those deaths.
Former Tokyo Electric Power Company Chairman Katsumata Tsunehisa and former vice presidents Takekuro Ichiro and Muto Sakae were indicted in 2016.
Court-appointed lawyers acting as prosecutors charged them with professional negligence resulting in death and injury. This was based on a decision by a prosecution inquest panel composed of randomly chosen citizens.