Leira may refer to:
Leira is a river in Oppland and Akershus, Norway. It comes from Leirsjøen, above sea level, in Romeriksåsene between Hadeland and Romerike, in Lunner municipality in Oppland. From here, it runs east through the countryside to Nannestad municipality in Akershus, and exits in Stråtjern, above sea level). It comes down to Romerikssletten westwards, until Maura and swings southwest, until it joins the Rotua and moves southeast and then southwards. Southwest of Gardermoen it runs through land between Nannestad and Ullensaker, along Gjerdrum and Ullensaker, and Gjerdrum and Sørum municipalities. Northeast of Hekseberget it joins the Gjermåa, and at the same time runs into Skedsmo municipality. Later, it passes through Frogner and Leirsund, runs into a meander over the flat lands around Lillestrøm, and exits into the Nitelva. It ends in the land between Skedsmo and Fet.