Elsa O'Riain (born 20 September 1982) is an Irish former professional tennis player.

O'Riain has a career-high singles ranking by the WTA of 382, reached on 21 October 2002.

She also has a career-high WTA doubles ranking of 295, achieved on 22 September 2023.

[1] O'Riain has won one singles and seven doubles titles on the ITF.

In September 2002, she won the ITF 25K tennis tournament in Glasgow, United Kingdom, with partner Yvonne Doyle.