Gov. Charlie Baker has been ramping up his public support for expanding the number of charter schools in Massachusetts.

The governor helped launch a so-called "fact check" effort last week to try to fight back against what he said was misinformation about what students charters serve and how they're funded.

Baker was back at it again this week, celebrating the finalists for an $80,000 charter school prize from the pro-charter Boston Foundation that'll be awarded to one of two Boston-area charters in June.

Baker's renewed push for charter reform comes as a group of public school advocates plan to rally at City Hall and the State House Wednesday to protest cuts to public ed funding.

Charters are a huge priority for Baker, who says the single biggest problem in education is the achievement gap.

"And the gap is our inability, collectively, as a commonwealth, to create the kinds of education opportunity and success, mostly for kids from communities of color to success and perform at the same level as the kids from the suburbs," Baker said Tuesday.

But Barbara Madeloni, the president of the Massachusetts Teacher Associations, says the governor's claims that successful charters help, not hurt, neighboring district schools is just flat out untrue.

"Part of why he is promoting it so heavily is that the pro-charter advocates are aware that the narrative about charters is changing across the state. People are realizing that they aren't providing quality education," Madeloni said.

The cap on the for-profit public schools could get lifted one of two ways: either the Legislature approves a compromise bill the Senate is currently trying to pass or the question will appear before voters on this year's ballot.