We present the first records of Coquillettidia (Coquillettidia) buxtoni (Edwards, 1923) (n=15), Culex (Neoculex) impudicus Ficalbi, 1890 (n=12), Culex (Neoculex) territans Walker, 1856 (n=52), Culiseta (Culicella) fumipennis (Stephens, 1825) (n=535), and Culiseta (Culicella) morsitans (Theobald, 1901) (n=54) in the Autonomous Community of Galicia (NW Spain), including the first evidence of the genus Coquillettidia Dyar, 1904 in the northwest of Spain. The field research was carried out in different water ecosystems (ponds, streams, rivers, lakes, and lagoons) belonging to 39 zones throughout the entire Galician territory. The samples were collected intermittently and seasonally through different projects of water quality monitoring between 1998 and 2018. A total of 1,614 mosquito larvae have been analyzed, and 668 of them were identified as species not previously recorded in Galicia. Between 1999 and 2003, the first catches of these species were obtained and since then, more specimens have been detected in different wetlands of Galicia, mainly in spring and summer.