Leon Lemmens (born March 16, 1954 in Boorsem, Maasmechelen, Belgium) is a Roman Catholic auxiliary bishop in Belgium.
Lemmens was ordained a priest on July 10, 1977. He was appointed Auxiliary Bishop to the Archdiocese of Mechelen-Brussel by Pope Benedict XVI on February 22, 2011 and ordained bishop on April 3, 2011.
Lemmens followed high school at the Klein Seminarie in Sint-Truiden. He entered seminary in Sint-Truiden (1971-1976) and was ordained to the priesthood to the Diocese of Hasselt on 10 July 1977. He obtained a bachelor in theology at the KU Leuven (1976) and studies moral theology in Rome. He obtained a licentiate in moral theology (1979) and became doctor in theology in 1989.
He worked as a parish priest in Genk (1981-1984). In 1984 he became professor at the seminary in Hasselt. From 1986 to 1997 he was a member of the Interdiocesan Commission on Liturgy and from 1990 to 1995 he was responsible for vocations. In 1994-1995 he took charge of the organisation of the meeting of young people with the pope in Brussels.
In 2004 he became rector of the Romanian College in Rome and in 2005 he was an official at the Sacred Congregation for the Oriental Churches of the Roman Curia,.
Leon Lemmens has been a member of the Community of Sant'Egidio since 1977.
On 22 February 2011, pope Benedict XVI appointed Lemmens as auxiliary bishop in the archdiocese of Mechelen-Brussels, with the responsibility for the vicariate Vlaams-Brabant & Mechelen. He is a Municipa.
He was consecrated on 3 April 2011 in the National Basilica of the Sacred Heart in Koekelberg by archbishop André-Joseph Léonard.