The inaction inertia effect refers to the idea that when people miss out on an initial opportunity, they are prone to stay inactive afterward. However, little is known about how personality relates to inaction inertia. The purpose of this research is to investigate the role of regulatory mode in the inaction inertia effect. Study 1 found that an assessment mode positively predicts inaction inertia while a locomotion mode is not related to inaction inertia. Study 2 replicated this finding in a different scenario. Study 3 found that priming assessment mode (compared with locomotion mode) predicts inaction inertia. Implications of how regulatory mode influences inaction inertia are discussed.