NAK (Novosadski atletski klub) (Serbian Cyrillic HAK (Hoвocaдcки aтлeтcки клуб); Hungarian: UAC (Újvidéki Athlétikai Club)) was a football club from Novi Sad that existed from 1910 until 1945.
Formed in 1910 while Novi Sad was still part of Austria-Hungary, the club mostly gathered players of Hungarian ethnicity. The town also had other football clubs that were similarly ethnically-based, namely FK Vojvodina, which was mostly Serb, and Juda Makabi, representing the local Jewish community. NAK competed in the Hungarian Second League between 1911 and 1914.
After the First World War the region became part of the Kingdom of Serbs, Croats and Slovenes, renamed Yugoslavia in 1929, and the club begin competing in the League of the Subassociation of Novi Sad, a second level which gave access to the Yugoslav First League. In 1922 NAK played in the qualifiers for the first edition of the First League however it was eliminated by its city rivals FK Vojvodina.
NAK mostly played in the Novi Sad Football Subassociation until they finally managed to qualify for the top league in 1935. The 1935–36 Yugoslav Football Championship was played in a cup format and NAK managed to post a series of good results. They eliminated ŽAK Velika Kikinda in the round of sixteen by 4–0 at home and a 3–3 away draw, thus qualifying to the quarter-finals where they beat Slavija Osijek with a double victory of 4–0 and 2–0. They were eventually stopped in the semi-finals where after achieving a draw in Sarajevo against FK Slavija unexpectedly lost at home by 1–3. In the period between the two world wars, Novi Sad saw a fiercy rivalry developed between NAK and FK Vojvodina.