The ‘resource curse’ associated with natural resource abundance has long been a subject of study across multiple disciplines. Though much research has focused on possible effects of resource wealth on the formal economy, little is known about how such wealth affects the informal sector, a substantial portion of global economic activity. We posit that resource windfalls directly contribute to growth in the informal economy, as investment and spending patterns associated with such revenues limit opportunities within the formal sector and thus channel more labor and businesses into the informal sector. We test these claims across a panel of over 120 countries for the period 1985 to 2012. Across multiple model specifications, we find that resource wealth growth is associated with increased informal economic activity.