Maksimilijan Matjaž (born 23 August 1963) is a Slovenian prelate of the Catholic Church, serving as the third bishop of the Diocese of Celje since 5 March 2021.

Maksimilijan Matjaž was born into a Catholic family in Črna na Koroškem in northern Slovenia (then part of Yugoslavia).

Matjaž was engaged in the pastoral work and served as an assistant priest in Zreče (1989–1991).

In summer 1991 he continued his education in the Collegium Germanicum et Hungaricum and completed his studies with a licentiate degree in a Biblical theology in 1995 at the Pontifical Biblical Institute and with a Doctor of Theology degree in the same discipline at the Pontifical Gregorian University in 1998.

On 30 May 2021, Apostolic Nuncio to Slovenia consecrated Matjaž as bishop in the St. Mohorij in Fortunata Church in Gornji Grad.