The room‐temperature synthesis of a new two‐dimensional (2D) zirconium‐containing carbide, Zr3C2Tz MXene is presented. In contrast to traditional preparation of MXene, the layered ternary Zr3Al3C5 material instead of MAX phases is used as source under hydrofluoric acid treatment. The structural, mechanical, and electronic properties of the synthesized 2D carbide are investigated, combined with first‐principles density functional calculations. A comparative study on the structrual stability of our obtained 2D Zr3C2Tz and Ti3C2Tz MXenes at elevated temperatures is performed. The obtained 2D Zr3C2Tz exhibits relatively better ability to maintain 2D nature and strucural integrity compared to Ti‐based Mxene. The difference in structural stability under high temperature condition is explained by a theoretical investigation on binding energy. Zr3C2Tz nanosheets: A 2D zirconium‐containing carbide, Zr3C2Tz MXene, is obtained by selective etching of Al3C3 units from layered ternary Zr3Al3C5 beyond MAX phases (see picture) at room temperature. The structural, mechanical, and electronic properties of the 2D carbide were investigated combined with density functional calculations. The 2D Zr3C2Tz exhibits excellent thermal stability, which exists even at 1200 °C in vacuum.