Brunei Darussalam is a small open economy gifted with important oil resources which make it the second richest Southeast Asian economy after Singapore. Like all resource-rich countries, its main challenge is to diversify its activities to prepare for a post-oil sustainable economy. Attracting foreign direct investment in new sectors will be an important element of success in this endeavour. The legal framework governing investment will therefore be critical to foreign investors. Although the experience of Brunei in international investment treaties negotiations is rather limited from a quantitative point of view, the country has signed several treaties with partners such as China, Korea, Japan, and the other ASEAN countries. This chapter reviews the existing treaties with the object of assessing Brunei's contribution to international investment policy in Asia and explaining Brunei's trajectory in terms of investment rule-making, FDI trends and potential disputes.