Mariano-Florentino "Tino" Cuéllar (born July 27, 1972) is an American scholar, jurist, and nonprofit executive currently serving as the 10th president of the Carnegie Endowment for International Peace.

When he was in law school, Cuéllar co-founded a not-for-profit organization providing opportunities for students to teach English in under-served communities,[11] and spent summers working at the U.S. Senate and the President's Council of Economic Advisers.

[12] After law school, Cuéllar worked at the U.S. Department of the Treasury, and clerked for Chief Judge Mary M. Schroeder on the U.S. Court of Appeals for the Ninth Circuit.

At Stanford, he also served as Co-Director of the university's interdisciplinary Center for International Security and Cooperation (CISAC), working with former Los Alamos National Laboratory Director Siegfried Hecker.

[15] During the years he led the Freeman Spogli Institute and CISAC, Cuéllar grew the Institute's faculty, launched university-wide initiatives on global poverty and on cybersecurity, expanded Stanford's role in nuclear security and arms control research and policy, increased support for global health and governance projects, and broadened opportunities for student and faculty research abroad.

To reduce the nation's achievement gaps, the report recommended local, state, and federal reforms addressing school finance and efficiency, teaching and learning opportunities, early childhood education, and other areas.

On July 22, 2014, Governor Brown nominated Cuéllar to the California Supreme Court, filling a vacancy created by the retirement of Justice Marvin Baxter.

In addition to serving as Director of the Freeman Spogli Institute and leading CISAC, he led the Stanford Cyber Initiative, and earlier, the Honors Program in International Security Studies.

His record has been described as reflecting a “practical view of the law that shows in both his questions during hearings and in his written rulings.” [38] Cuéllar "wrote some of the court’s highest profile rulings and led an effort to break down language barriers in courthouses throughout the state.

]"[41] SoCalGas Cases (2019), ruling that businesses impacted by the release of methane and other gases from the massive Aliso Canyon gas leak cannot recover in negligence for purely economic losses, because recovery for such losses generally requires a “special relationship” and “the ripple effects of industrial catastrophe on this scale in an interconnected economy defy judicial creation of more finely tuned rules.”[42] De la Torre v. CashCall (2018), concluding that interest rates on consumer loans can be so high that they become “unconscionable” and therefore void under California law.

[46] Cleveland National Forest Foundation v. San Diego Association of Governments (2017)(dissent), concluding that San Diego’s multi-decade regional transit plan did not adequately disclose its failure to contribute materially to the achievement of California’s greenhouse gas emissions reduction goals to avert climate change, despite the feasibility of reasonable alternatives that could have achieved greater compliance with California’s climate related goals.

[48] He has worked on several ALI projects, including Model Penal Code: Sentencing,[49] Principles of Government Ethics,[50] and Restatement Fourth, The Foreign Relations Law of the United States.