Jean-Nicolas Lemmens (also Joannes Nicolaas Lemmens or Joannes Nicolaus Lemmens) (Schimmert, 3 June 1850 – Cobán (Guatemala), 10 August 1897) was a Dutch Catholic priest and Bishop of Victoria, Vancouver Island, Canada. He was a strong supporter of the British Columbian organised labour movement.
Jean-Nicolas Lemmens was born the son of Godfried Lemmens and Gertrude Bemelmans, within a large Dutch Roman Catholic, family originating from the Beek-Schimmert area in the southern Netherlands.
His family produced a number of catholic priests, including his brother, Hendrik Lemmens, also a priest in Victoria, Canada, and Guillaume Lemmens (1884-1960), Bishop of Roermond in the Netherlands.
Lemmens studied at the American College in Louvain, Belgium, which was founded in 1857. He then moved, with his brother, to Vancouver Island, Canada.
After the murder of Monseigneur Seghers in 1888 he was appointed Bishop of Victoria. He laid the foundation stone of St. Andrew's Cathedral in 1890, which can still be seen near the side entrance. On 30 October 1892 he consecrated the Cathedral.