The Diocese of Ciudad Quesada is a Latin Church ecclesiastical territory or diocese of the Catholic Church in Costa Rica.

It is a suffragan diocese in the ecclesiastical province of the metropolitan Archdiocese of San José de Costa Rica.

Ciudad Quesada is the capital of the District of Ciudad Quesada, and of the larger Canton of San Carlos, which is in turn part of Alajuela Province.

On 31 December 2012, Pope Benedict XVI accepted the resignation of Bishop Oswaldo Brenes Álvarez from the pastoral governance of the diocese; there was no immediate replacement, so the diocese was a sede vacante (vacant see).

This article about a Catholic diocese is a stub.