Dalin is a Swedish surname. The name frequently appears as Dahlin. Both surnames are derived from the Swedish word dal meaning valley. Notable people with the surname include:
Charlie Dalin (1984–2026), French offshore sailor David G. Dalin (born 1949), American historian Kalle Dalin (born 1975), Swedish orienteering competitor Marius Langballe Dalin (born 1966), Norwegian politician Olof von Dalin (1708–1763), Swedish poet Per Dalin (1936–2010), Norwegian educationalist