Maciej Cieślak (born 9 September 1969 in Gdańsk) is a Polish guitarist and songwriter, best known as the vocalist and guitarist of the alternative rock band Ścianka, which he founded in November 1994 in Sopot.
Its first releases, P.O.L.O.V.I.R.U.S. by Tymon Tymański's Kury and Statek kosmiczny Ścianka by Ścianka were big artistic and commercial success on polish alternative music market, winning together seven nominations for Fryderyk Award (six for Kury and one for Ścianka) and one award.
In 2000, Lenny Valentino underwent further personnel changes and added all three members of Ścianka—Maciej Cieślak (guitar), Arkady Kowalczyk (drums), and Jacek Lachowicz (keyboard).