This Occasional Paper prepared by Bank Indonesia served as a background paper to facilitate discussions on Financial Deepening to Support Monetary Stability and Sustainable Growth among the SEACEN Governors at the 43nd SEACEN Governors Conference held on 21 March 2008 in Jakarta Indonesia. The Paper delve into stages of financial deepening in SEACEN economies for the banking sector and also the capital and money market. The Appendix was prepared by The SEACEN Centre to provide cross country information on financial deepening monetary stability and economic growth in the SEACEN Region.