"I'm against gay marriage"-Donald Trump, 2011

On a pro-lgbt law that passed: "I would of liked to see the decision differently"

He spoke at a large Anti-Gay Evangelical Christian meeting, asking for their support.

Supports the North-Carolina Anti-LGBT Bathroom Bill

He pledged to sign the First Amendment Defense Act, which if passed, it would legalize LGBT discrimination among employers, businesses, landlord and healthcare providers.

Mike Pence, his VP pick, signed into law a religious objections bill that that many saw as condoning discrimination against LGBT people.

Trump Said He Would “Strongly Consider” Appointing Judges To Overturn Same-Sex Marriage Decision.

Trump Said He Would Undo President Obama’s LGBT Executive Orders On His First Day In Office.

Trump Referred To Caitlyn Jenner By Former Name And Pronouns And Criticized The Ratings For “I Am Cait.”

Trump Said He Would “Absolutely” Support Hate Crimes Legislation And One Of His Greatest Disappointments With George W. Bush Was His Failure To Push For A Bill.

Trump Said he Sided with “the State” and Defended HB2.

The Human Rights Campaign's summary of Donald Trump's stances on Marriage Equality, Discrimination, and Transgender Equality:

Marriage: Trump has been a consistent opponent of marriage equality. He said that he opposed it because he was a “traditional” guy, choosing to support domestic partnership benefits instead. Trump later reversed himself and said he also opposed civil unions. Despite a brief flirtation with “evolving” in 2013, Trump has consistently maintained his opposition to marriage equality, sometimes by citing polling and making an analogy to his dislike of long golf putters. After the Supreme Court ruling, Trump said the court had made its decision and, although he disagreed with the ruling, he did not support a constitutional amendment that would allow states to re-ban marriage equality. He later said he would appoint Supreme Court judges who would be committed to overturning the ruling.

Discrimination: While Trump at one time said that federal law should protect people from discrimination based on sexual orientation, he has taken aggressively anti-equality positions as a formal candidate. Trump has expressed support for the so-called First Amendment Defense Act (FADA) which would lead to more Kim Davis-style discrimination. He has declined to support the Equality Act.

Transgender Equality: Trump has expressed support for North Carolina’s HB2, he’s said he would rescind the Obama Administration’s guidance that transgender students be treated wtih dignity and allowed to use restrooms that match their gender identity, and when it comes to governors like Pat McCrory that write discrimination into state law, Trump has made it clear he would not enforce federal civil rights laws ensure transgender Americans are treated equally under the law.

http://www.hrc.org/2016RepublicanFacts/donald-trump-opposes-nationwide-marriage-equality#protection