The 29-year-old Canadian netminder told the Washington Post on Friday that he will skip the private White House tour and Oval Office meeting with US President Donald Trump, joining forwards Brett Connolly and Devante Smith-Pelly who have opted out of the tribute trip.
"I've got to stay true to my values and I'm going respectfully decline the offer," Holtby said. "In saying that, it's a tough situation for everyone to be in, to be forced to make a decision of that standing.
"You're a team and you want to stick together no matter what, so I hope everyone kind of blows it away and that we don't worry about who goes and who doesn't."
Holtby, who has been involved with NHL outreach "You Can Play" to combat homophobia and spoke at last year's Human Rights Campaign national dinner, said he could not go and be true to his values.
"For me, it's just a personal thing," Holtby said. "I believe in what I believe in, and in order to stick to those values, I think I have to do what I feel is right.
"My family and myself, we believe in a world where humans are treated with respect regardless of your stature, what you're born into.
"You're asked to choose what side you're on and I think it's pretty clear what side I'm on. I believe that this is the right decision for myself and my family."
Smith-Pelly, a Canadian right wing who is black, told Canada's Postmedia he would decline a White House visit because "the things that (Trump) spews are straight-up racist and sexist."
Holtby, in his ninth NHL campaign, has 27 wins in 52 starts with a 2.95 goals-against average for the Capitals, who lead the Metropolitan Division with 43 wins and 94 points from 74 games.
Washington beat the Vegas Golden Knights in last year's Stanley Cup Final. This year's regular season ends in two weeks.
The Capitals said there will be no official ceremony or media availability during their White House visit, a rare low-key stopover compared to past champions' visits.
Trump has canceled some team visits to the White House, including 2018 Super Bowl champion Philadelphia Eagles and the 2017 and 2018 NBA champion Golden State Warriors, after players said they would not attend.
In January, the Warriors instead visited former US President Barack Obama in his Washington office before a game against the Washington Wizards. A year ago, they visited the National Museum of African-American History and Culture.