SEK (Sidirodromoi Ellinikou Kratous, Hellenic State Railways) Class Θγ (or Class Thg; Theta-gamma) was a class of 2-8-0 steam locomotives ex-United States Army Transportation Corps S160 type.

In 1959, Italian Railways (Ferrovie dello Stato, FS) sold another 25, formerly Class 736, Nos 736.011/23/40/55/73/90/101/2/126/7/131/5/51/8/60/4/6/78/88/90/9/203/7/9/17 to SEK.

Four are at Thessaloniki Old Depot (Θγ 525, 532, 535, 584), one is outside Thessaloniki current depot (Θγ 593) whilst one more survives at Tithorea depot (Θγ 576).

[1] Θγ 575 is under overhaul at the Churnet Valley Railway in Great Britain.

This steam locomotive-related article is a stub.