Valcău de Jos (Hungarian: Alsóvalkó) is a commune in Sălaj County, Crișana, Romania.

It is composed of six villages: Lazuri (Újvágás), Preoteasa (Füzespaptelek), Ratovei (Rátonbükk), Sub Cetate (Valkóváralja), Valcău de Jos, and Valcău de Sus (Felsővalkó).

Its castle was built in the late 13th century, and was unlawfully occupied by Dezső Elefánti in 1312.

In 1910 the village had 900 residents, with a Romanian majority and a significant Hungarian minority.

At the 2021 census, Valcău de Jos had a population of 3,009, of which 75.74% were Romanians, 17.88% Roma, and 1.6% Hungarians.