RUSI is a Registered Charity (No. 210639). It relies on membership subscriptions; income from conferences including sponsorship; research contracts; room hire; and donations from foundations and individuals for its income. RUSI receives no core funding from government.

Diversity in the UK's Intelligence Agencies
Financing Right-Wing Extremism and Terrorism
New UK Government Initiative to Support High-Risk, High-Reward Military Science Needs Refinement