Former Mayor Rudy Giuliani was a last-minute no-show at the wedding of his former roommates — a gay couple — yesterday.

It was a disappointment for Queens car dealer Howard Koeppel and his longtime lover, Mark Hsiao, who tied the knot in a double-ring ceremony before 10 guests in Westport, Conn.

The couple famously let the ex-mayor crash at their luxury $2.37 million three-bedroom Manhattan apartment while he was going through a nasty divorce with Donna Hanover in 2001. Later, Giuliani married the “other woman,” Judith Nathan.

“Rudy and Judith were both invited with a beautiful written invitation by mail,” said Koeppel. “His secretary called Thursday and said he was not able to come to the wedding and wished us all the best.”

Koeppel once quipped that Giuliani was a perfect roommate who “always made his bed” and “called me mother.”

At the time, Giuliani ducked the question about whether living with a gay couple had changed his longstanding opposition to gay marriage.

“I don’t relate to people as white, black, Catholic, Protestant, Jewish, gay, lesbian, heterosexual,” the then-mayor told reporters at Gracie Mansion.

Giuliani has stated he has no problem with civil unions but told The Post he’d speak out against gay marriage if he runs for governor. Connecticut in November allowed gays to marry.