Kazimierz Wincenty Iranek-Osmecki (noms de guerre Kazimierz Jarecki, Wlodzimierz Ronczewski, Makary, Antoni Heller, Pstrag; 5 September 1897 – 22 May 1984, London) was an infantry colonel (pulkownik) in the Polish Army, and colonel in Poland's Home Army (AK).
He fought in the 1944 Warsaw Uprising, and was responsible for negotiations between the Home Army and the German Wehrmacht.
Iranek-Osmecki commanded the Home Army General Staff's Section II (Intelligence and Counterintelligence), and was a Cichociemny.
He discovered the German V-1 and V-2 testing facility at Peenemünde.