Samuel Kamau Wanjiru (10 November 1986 – 15 May 2011) was a Kenyan long distance runner.
He set the current 10,000m World Junior Record in 2005 and set the half marathon world record 3 times.He moved to the full marathon and won the event at the 2008 Beijing Olympics in an Olympic record time of 2:06:32; becoming the first Kenyan to win the Olympic gold in the marathon.
He became the youngest gold medallist in the marathon since 1932.
The following year, he won both the London Marathon and Chicago Marathon, running the fastest marathons ever recorded in the United Kingdom and United States, respectively.
He retained his Chicago title in 2010 in a season fraught with injury.
In 2011, he died after a fall from a balcony at his home in Nyahururu following a domestic dispute.
Police were uncertain whether his death was a suicide, homicide, or accidental.