The Co-cathedral of Santa María la Mayor (Spanish: Concatedral de Santa María la Mayor) is a co-cathedral located in Guadalajara, in Castile-La Mancha, Spain.

It is one of the seats of the Roman Catholic Diocese of Sigüenza-Guadalajara.

The building was built in the Mudéjar style.

It was declared Bien de Interés Cultural on 12 July 1941.

This article on a Roman Catholic cathedral in Spain is a stub.