The 1985 Monte Carlo Open (also known as the Jacomo Monte Carlo Open for sponsorship reasons) was a men's tennis tournament played on outdoor clay courts at the Monte Carlo Country Club in Monte Carlo, Monaco that was part of the 1985 Nabisco Grand Prix. The tournament was held from 1 April through 7 April 1985.

Ivan Lendl defeated Mats Wilander, 6–1, 6–3, 4–6, 6–4

Pavel Složil / Tomáš Šmíd defeated Shlomo Glickstein / Shahar Perkiss, 6–2, 6–3