First-team coach Andy Smith, goalkeeping coach Marco Tabuas and fitness coach Maykel Moreira have now also left Vale Park, the League One club has confirmed.
The three all arrived when Ribeiro was appointed in the summer.
"We thank them for their time with us," a club statement said.
"They helped assist the club to their best home start to a season ever at Vale Park and progression to the FA Cup third round."
Vale face a home game with Chesterfield on Friday before a trip to Oldham on Monday, prior to playing Championship side Huddersfield Town in the FA Cup on 7 January,
They have lost their last three league games to slip to 17th in the table - just six points above the relegation zone.
Ribeiro's former assistant, Michael Brown, has been placed in temporary charge of the Burslem-based club.
Port Vale have parted company with three of their backroom staff after manager Bruno Ribeiro's Boxing Day departure.