Studies of land property rights usually focus on tenure security and transfer rights. Rights to determine how to use the land are regularly ignored. However, user rights are often limited. Relying on a unique Vietnamese panel data set at both household and plot levels, we show that crop choice restrictions are widespread and prevent crop diversification. Restrictions do not decrease household income, but restricted households work harder, and there are indications that they are supplied with higher quality inputs. Our findings are consistent with the view that it is possible to intervene effectively in agricultural production to promote output and food security. Nevertheless, potential benefits of a more diversified crop pattern must be carefully considered in a period where global food markets are in turmoil.