Simon Best (born 11 February 1978) is a former Irish rugby union rugby player. He played for Ulster and was club captain in Ulster's 2005–06 Celtic League winning season. Best missed the final game of Ulster' successful campaign in 2005/06 due to a broken ankle sustained while playing against Llanelli Scarlets in the penultimate game of the season.
On 26 September 2007 Best was rushed to hospital in Bordeaux with a loss of feeling down his side. He was immediately pulled out of the Ireland World Cup side and returned home. On 25 February 2008, Best announced his retirement from rugby due to an irregular heartbeat. He stated he would no longer be able to sustain the high level of training that playing professional rugby required.