Venanzio Ortis (born 29 January 1955) is an Italian retired long-distance runner who won two medals at the 1978 European Championships.

On 16 August 1978, aged 23, he set a new Italian record in the 5000 m at the Weltklasse Zürich, obtaining a third place behind Henry Rono and Markus Ryffel.

In the fast 10,000-metre race of the 1978 European Athletics Championships, held in Prague two weeks later, he broke 28 minutes for the first time while finishing second in 27 minutes 31.48 seconds, just four one-hundredths of a second ahead of Aleksandr Antipov of the Soviet Union, and half a second behind Finland's Martti Vainio (see, for example, Tapio Pekola et al., eds., EM-Praha 1978 (European Championships in Prague 1978), Kaarina, Finland: Juoksija-lehti (Runner Magazine), 1978).

In the slow and tactical 5,000-metre final, he managed to squeeze through the narrow space between Ryffel and the Soviet Union's Aleksandr Fedotkin to sprint to the lead and win by 0.1 seconds.

His last major international track race was the 1981 IAAF World Cup event in Rome, where he placed fourth in 10,000.