Interactions between foreign investment and host community raise questions as to the proper approach to balance investment protection and sustainable development interests. This article examines how Tanzania balances investment protection with social and environmental concerns. Tanzania has had a mixed practice with foreign investment and Bits. Few Bits were concluded in the early years after independence. But then the country experimented with socialism and self-reliance in late 1960’s and 1970’s, only to reverse trend in mid-1980’s. Tanzania concluded majority of her Bits in 1990s and 2000’s. From 2010, Tanzania concluded Bits which are conscious of sustainable development concerns. Tanzania-Canada BIT is a case in point. These Bits not only inserted explicit sustainable development provisions but also progressive investment standard provisions which afford the government space to regulate legitimate sustainable development objectives. However, this recalibration approach still faces practical challenges due inconsistencies of arbitral tribunals. To help fill this gap, the study considers the role of domestic investment laws in protecting sustainable development interests. In that regard, the study holds the view that domestic investment laws have to be sustainable development oriented in order to supplement other approaches of balancing investor rights with sustainable development interests of host states.