MLB posted the statement on its website, as pressure mounted on Arizona Gov. Jan Brewer to veto the bill, which permits businesses to deny services to gays and lesbians on grounds of religious objection.
"As the sport of Jackie Robinson, Major League Baseball and its 30 Clubs stand united behind the principles of respect, inclusion and acceptance," the statement said. "Those values are fundamental to our game's diverse players, employees and fans. We welcome individuals of different sexual orientations, races, religions, genders and national origins.
"MLB has a zero-tolerance policy for harassment or discrimination based on sexual orientation, as reflected by our collective bargaining agreement with the MLB Players Association," the statement said. "Accordingly, MLB will neither support nor tolerate any words, attitudes or actions that imperil the inclusive communities that we have strived to foster within our game."
A growing number of companies and business interests have urged Brewer to veto the bill. Brewer has not yet indicated whether she will veto or sign the bill.
If she takes no action by Saturday, the bill will become law.
NFL officials are looking into moving the 2015 Super Bowl from Arizona if the bill becomes law, Sports Illustrated reported Wednesday.