Ucelay is a Spanish surname. Notable people with the surname include:
(born 1965), Spanish sports journalist Enric Ucelay-Da Cal (born 1948), American historian specializing in contemporary history José María Ucelay (1903–1979), Spanish painter, illustrator, and decorator (1916–2014), Spanish philologist Matilde Ucelay (1912–2008), the first woman licensed in architecture in Spain (1913–1986), Spanish municipal architect