Xiuhtezcatl Roske-Martinez (/ʃuːˈtɛzkɑːt/ shoo-TEZ-kaht; born May 9, 2000), also known by the initial X,[a] is an American environmental activist and hip hop artist.

Martinez was one of 21 plaintiffs involved in Juliana v. United States, a lawsuit filed in 2015 against the U.S. government for failing to act on climate change.

[9] His mother, Tamara Roske, was one of the founders of the Earth Guardian Community Resource Center, a high school in Maui, Hawaii.

His father, Siri Martinez, raised him with an appreciation for the tradition of the Mexica, one of the historic Indigenous peoples of Mexico, today often grouped under the Nahua.

"[11] As a teenager, Martinez gave TED talks and was invited to speak before the United Nations on environmental policy.

[19][12][20][21][22] Earth Guardians' mission is to "inspire and train diverse youth to be effective leaders in the environmental, climate and social justice movements.

Through the power of art, music, storytelling, civic engagement, and legal action, we're creating impactful solutions to some of the most critical issues we face as a global community.

"[23] They work to organize climate strikes, cultivate environmentally focused policy, and encourage individual activism through promoting voting registration.

The plaintiffs originally included parties from the fossil fuel industry as defendants in the lawsuit but they were removed during pre-trial proceedings.

[27] In December 2018, Martinez spoke with Sanders at a town hall event called "Solving the Climate Crisis".