Nikolaj Frederik Severin Grundtvig (Danish: [ˈne̝koˌlɑjˀ ˈfʁeðˀˌʁek ˈse̝vəˌʁiˀn ˈkʁɔntvi]; 8 September 1783 – 2 September 1872), most often referred to as N. F. S. Grundtvig, was a Danish pastor, author, poet, philosopher, historian, teacher and politician.

N.F.S. Grundtvig (born September 8, 1783, Udby, Denmark—died September 2, 1872, Copenhagen) Danish bishop and poet, founder of Grundtvigianism, a theological movement that revitalized the Danish Lutheran church. He was also an outstanding hymn writer, historian, and educator and a pioneer of studies on early Scandinavian literature.

N.F.S. Grundtvig var en dansk præst, digter og politisk skikkelse. Hans tanker om folkelighed, religiøs tro, samfundsliv og nationalitet har fået afgørende betydning for dansk åndsliv, politisk kultur, folkeoplysning, kirkeliv og tro.