In Thailand’s emerging democracy, the Senate has played an often underestimated role. This study analyzes Thailand’s Upper House, examining its historical evolution until 2009. In particular, it focuses on the following questions. What innovations did the 1997 Constitution bring to the Senate? How and why was the Senate adjusted under the 2007 constitution? The study further reviews the Senate elections of 2000 and 2006 as well as the election/selection of 2008. Finally, it postulates as to the continued significance of an Upper House in Thailand and offers recommendations for the future course of Thailand’s developing Senate.