Brazilian President Jair Bolsonaro had wanted to mark the 55th anniversary of the coup and had ordered the military to plan a celebration for the overthrow of the government of President Joao Goulart.
Judge Ivani Silva da Luz barred Sunday’s plans, saying the widely criticized observance was not “compatible with the process of democratic reconstruction.” The judge added that commemorative dates must be approved by Congress.
Brazilian citizens have been organizing through social media to mount demonstrations Sunday against the military dictatorship and to remember its victims.
During the 21-year-long dictatorship, at least 434 people were killed or disappeared.
No military officials have been prosecuted for any crimes committed during that time.
Bolsonaro has expressed his affinity for dictators on several occasions.