--- - |2 Abstract Although group‐related uncertainties have been shown to drive subgroups’ pursuit of autonomy, it is unclear whether all group‐related uncertainties motivate subgroup autonomy. We hypothesized that social identity‐uncertainty, not politico‐economic uncertainty, about one’s subgroup is a key driver of support for subgroup autonomy. We measured Sardinian participants’ (N = 174) relative subgroup (Sardinian) and superordinate group (Italian) identity‐centrality, identity‐uncertainty, and politico‐economic uncertainty to predict support for subgroup autonomy and superordinate group fragmentation. Results showed that subgroup identity‐uncertainty, not politico‐economic uncertainty, elicited stronger support for subgroup autonomy, especially among highly identified subgroup members. Superordinate group fragmentation was predicted by relatively weaker superordinate identity‐centrality. Results suggest that subgroups’ pursuit of autonomy is driven by the hopes of reducing identity‐uncertainty. - Journal of Applied Social Psychology, Volume 48, Issue 10, Page 582-589, October 2018.