Tenure insecurity can have important consequences for the conservation of natural resources. This paper focuses on two main sources of tenure insecurity, informal short-term tenancy contracts, and customary gender-biased inheritance practices. Using a large plot-level dataset from Malawi, the analysis employs a linear probability model with household fixed effects and finds that both sources of insecurity have a negative effect on soil conservation investments. These findings suggest that future land reforms should deal with the informality of the land rental market and address the gap between users and owners of land created by existing customary practices.