Sergio Méndez Arceo (28 October 1907 in Tlalpan – 5 February 1992 in Morelos) was a Mexican Roman Catholic bishop, activist and human rights supporter.

A product of a wealthy family, Méndez Arceo's father was a successful lawyer and his uncle was a prominent archbishop believed to be involved in the church-state conflict of the 1920s.

[4] Méndez Arceo is quoted as saying; "I can assure you that all my actions have been motivated by the conviction that I cannot abandon my fellow man, my brothers, that I must bear witness to the fact that a true Christian has the obligation to condemn any form of injustice, particularly the sort of injustice which becomes a veritable institution, the prevailing order of things"[6]Méndez Arceo supported Ivan Illich, an Austrian philosopher, in setting up the Intercultural Documentation Center (Spanish: Centro Intercultural de Documentación) (CIDOC) at his diocese in Cuernavaca in 1961.

[11] Upon his retirement Méndez Arceo founded the Center for Meetings and Dialogue (CED) in Cuernavaca to serve as an umbrella organization for other social and activist programs in the state of Morelos.

Today, the CED "provides a regional mechanism for progressive popular organizations" as well as housing statewide meetings in various fields such as women's empowerment, human rights, education, and environmental protection.

As an individual without the support of the other bishops, Méndez Arceo assisted the imprisoned students, often called political prisoners, following the Tlatelolco Plaza massacre.

[5] Méndez Arceo visited Cuba where he received the Orden de la Solidaridad from Fidel Castro for his "merit in the struggle against imperialism, colonialism, neocolonialism and other forms of exploitation."

"[14] Some say that Sergio Méndez Arceo's actions and views made him too controversial, to the point that it limited his ability to form collegiality with other Mexican bishops and the episcopate; also that he politicized his diocese and its communities, and in doing so was opposed to the government.

It later become known that the United States Federal Bureau of Investigation (FBI) produced a report on Méndez Arceo stating he was friendly to the Farabundo Martí National Liberation Front (Spanish: Frente Farabundo Martí para la Liberación Nacional) (FMLN) of El Salvador and the Sandinista National Liberation Front (Spanish: Frente Sandinista de Liberación Nacional)(FSLN) of Nicaragua, which took power in 1979 following the collapse of the Somoza regime.

The FBI further alleged Méndez Arceo's diocese collected intelligence, bought and sold guns, and served as couriers for communist guerrillas of El Salvador.