Brownsburg High School has a policy that mandates teachers call transgender students by their preferred name, in place of their birth name.
John Kluge, who taught at the high school for four years, disagreed with the rule and said he instead wanted to refer to the student by their last name.
"I feel the compelled speech of forcing a teacher to take a side on this very highly controversial topic is a violation of our First Amendment rights," Kluge told ABC affiliate WRTV.
Kluge told WRTV the school told him he must either follow the policy, resign or be fired. He said he submitted a conditional resignation later, but later withdrew the resignation before the deadline.
A school district representative told WRTV that Kluge voluntarily submitted a resignation and the administration accepted it.
Kluge believed he would be suspended pending termination on May 1, according to WRTV. He called his meeting with the administration "very threatening" and "bullying."
"I enjoy being the orchestra teacher at Brownsburg," Kluge wrote in a statement. "It's unfortunate that the administration is not letting me come back and that they are unwilling to continue a reasonable accommodation that most people consider to be very common sense."
He went on to ask that the board reconsider his termination.
The administration told WRTV it's complying with all state and federal laws.
According to the Brownsburg Community School Corporation, a student is allowed to change their preferred name only with a letter from a parent and a health care professional.
"Showing a lack of support for transgender youth is what drives up the suicide rates of transgender youth in Indiana," Chris Paulsen, executive director of the LGBTQ organization Indiana Youth Group, told WRTV.