Stephen Obayan Sunday (born 17 September 1988), nicknamed Sunny, is a Nigerian former professional footballer who played as a defensive midfielder.

In 2003, he participated in two youth championships in Sweden and Spain: in the latter he appeared in Madrid's third edition of the Annual Immigrants World Cup, where he impressed so much he was given a five-year contract with Polideportivo Ejido, in the Segunda División.

[2] Sunny became a regular player for the Andalusia team, making 65 competitive appearances during his two-year spell and signing for Valencia in the summer, but after one season where he was scarcely used, he was loaned to fellow La Liga club Osasuna.

[21] Sunday, who was born in Nigeria, was eligible to play for Spain under FIFA rules allowing players with dual nationality and without full international caps to switch allegiance before the age of 21.

After first appearing for the under-19 side, he was called up by his adopted nation to the 2007 FIFA U-20 World Cup in Canada,[22][23] playing four games as the team exited in the quarter-finals.