Police ruled it a hate crime, and there was an international outcry, along with calls for tougher laws.
As CBS News correspondent Thalia Assuras notes, the beating was so savage that a description of his injuries, even a decade later, is hard to listen fathom.
"His head trauma consisted of a massive blow to the right side of his head," Rulon Stacey of Poudre Valley Hospital told reporters at the time. "It fractured his skull from behind his head in a horizontal fashion to in front of his right ear."
On the night of Oct. 6, 1998, Shepard left the Fireside Bar in Laramie with Aaron McKinney and Russell Henderson. The next morning, Shepard was found tortured and battered, tied to a fence. The biker who found him thought he was a scarecrow.
Shepard was mourned across the nation with candle light vigils.
His murder made hate crimes against gays a hot political issue, Assuras reports.
Celebrities such as Ellen DeGeneres pressed for understanding.
"Please raise your children with love and non-judgment," DeGedneres said. "Tell them that everyone has the right to love who they want to love. It shouldn't threaten you or who you are."
The Human Rights Campaign in Washington, the nation's largest gay rights advocacy group, cites statistics from the FBI showing hate crimes based on sexual orientation are the third most prevalent type, behind those based on race and religion, Assuras points out.
Human Rights Campaign president Joe Solomnese says, "We have to find increasing ways to try to address this violence. What I think needs to happen ... is not just the kind of legislative efforts that we're making, but really addressing this at its root, in schools and among young people" top change attitudes.
Wyoming still hasn't enacted any hate crime laws, Assuras says, making it one of 19 states that don't address hate crimes based on sexual orientation. It's something Shepard's family and friends still hope to change.
On The Early Show Monday, Shepard's mother, Judy Shepard, told co-anchor Maggie Rodriguez, "This whole week is just (one of) remembrances. It's a great sadness and sense of confusion, of loss. We've actually tried to address issues that haven't changed. It's been ten years. Why haven't things progressed further than they have?"
Judy says when that awful call first cam a decade ago, "We (she and her husband, Dennis) didn't really know what had happened. The circumstances and the facts were not known, but ... my first thought was, it happened because he was gay. You were just conditioned to think that that's going to happen, because someone's sexual orientation is different, that other people will hate them, will hurt them."
"Is that a hate? Is that a struggle that he lived with in his life?" Rodriguez asked.
"You know," Judy replied, "if he did, he didn't share it with us. We didn't -- weren't aware if he was ever harassed verbally before. We don't think he was physically, but we're not -- we don't know about verbally."
The two men responsible for Matthew's death are serving two consecutive life sentences, and Judy says the punishment fits the crime. "We are very satisfied that justice was done," Judy says. "There was absolutely no doubt that it was those two men. Both confessed, so it was, you know, they're paying the price for the decision they made."
Have they ever shown any remorse?
"To my knowledge, they have not. I'm pretty sure that they actually wonder still why they're in such trouble for what they did, just, you know, killing a young gay man. The environment was set up for them that it was OK to do that to Matt."
But, Judy says, there's been progress since Matt's death: "There's definitely been positive changes, and for a lot of reasons. Theatrical productions, literature, television, novels, movies, all portray the gay community in a very positive, forward-thinking way, and that has really helped. People understand the gay community.
"The level of ignorance is just -- it's amazing that people just don't know more about the civil rights that are being denied the gay community, and we're moving forward and working at the grassroots level now trying to really educate people and make them aware of the gay community."
Judy observed that Wyoming "is, I think, one of four states left with no hate crime legislation at all. Wyoming had the perfect opportunity to actually set the tone, set the example, just to be what every state should have been had that happened in their state, and they didn't take advantage of it."