The 27-year-old midfielder joined the club in July 2019 and has made 39 appearances in all competitions.
“I'm so happy to be committing my future to the club,”
said Ladd.
“To be a part of this squad is really special and I'm really enjoying my time here. When I first came to United, I knew I would be part of an ambitious group of players and staff and that mindset has only grown stronger over the last couple of years.
“We have an exciting time ahead of us and I know that if we continue to put the work in, day in, day out, then we can achieve our goals.