The 21-year-old has played 16 games for the Tigers, scoring six tries, since joining from York ahead of the 2016 season.
“I’m pleased to have extended my contract at Cas,” said Minikin.
“When my agent Craig told me Cas wanted to extend I was over the moon. I love it here at Cas and I’m really excited for next season.
“We have a bright future here at Castleford and we’re aiming to win some silverware if not next year then in the near future.
“I’m really excited with what is going on at the club and we’re really moving forward.”
Cas coach Daryl Powell is delighted that the player is staying put for a longer period.
“Greg Minikin became a real go to last year after we received so many injuries to the squad,” he said.
“He quickly showed that he is at home in Super League, from his first game against Leeds all the way through the season.
“He challenged defences with his natural running style.
“I have no doubt he will be a big player in Castleford Tigers future.
“I’m delighted he has extended his contract and look forward to seeing him improve further in the coming seasons.”