This chapter evaluates the shortcomings of state-led EIA processes in addressing Indigenous interests and the need for Indigenous participation in assessing projects that affect Indigenous territories. It shows how these shortcomings can be addressed through Indigenous Impact Assessment (IIA), an important and emerging form of impact assessment. The control or influence that Indigenous groups have in IIA extends into scoping, who conducts the IA, how the IA is conducted, and control over IA findings. The chapter considers the wider benefits of IIA for proponents, the state, and the environment. The analysis concludes that there is no ‘best practice’ for conducting IIA, reflecting the diversity of Indigenous peoples and contexts and the scope for innovation that IIA offers. The key issue is that in seeking to gain the most from IIA, Indigenous peoples face important choices, including whom to partner with, what methods and lenses of assessment to adopt, and where to focus their efforts given the limited availability of resources. IIA is likely to become more prevalent because it helps address structural power imbalances, gives expression to growing recognition of Indigenous rights, and reflects a greater willingness by state agencies and proponents to embrace collaborative EIA with Indigenous groups.