Roberts, who founded the transgender news website TransGriot in 2008, died Oct. 5, according to reporting by Outsmart Magazine, where Roberts was also a columnist.
"Today, we pause to remember the impact Monica has made in our city. I will personally miss her and am grateful for the friendship we developed over the years," Mayor Sylvester Turner said in a written statement. "Houston embraces everyone, no matter where they come from [or] their background and continues to be a place of hope and opportunity."
Houston City Council members also mourned the loss on social media.
"I learned so much from Monica and I’m saddened by the loss of this fierce advocate. Her passion and inclusive spirit will never be forgotten," Council Member Martha Castex-Tatum wrote.
"Heartbroken to learn of the passing of not just a local hero and firebrand, but a national leader. Monica Roberts, we love you and will continue to lift up your voice," Council Member Abbie Kamin wrote.
Harris County Sheriff Ed Gonzalez also shared a message of support on Twitter.
"Her fierce advocacy for trans rights was crucial and admirable. Let's vow to remember her and stand in solidarity to advance her work," he wrote.
The Harris County Democratic Party also shared its condolences.
“Monica was a fierce advocate for the LGBTQ community,” Party Chair Lillie Schechter said in a statement. “This is an enormous loss for the equal rights movement. She lobbied at the federal and local levels for transgender civil rights protection, and she worked tirelessly to educate and encourage acceptance of transgender people.”