Smartphone users often find mobile security notifications (MSNs) to be annoying and intrusive. MSNs are security warnings displayed on mobile interfaces designed to protect mobile phone users from security attacks. Traditionally, users are forced to choose between “Yes” (“Accept”) or “No” (“Ignore” or “Deny”) decisions in response to MSNs. However, in practice, to make MSNs less intrusive, a new “Remind Me Later” button is often added to MSNs as a third option. Consequently, this “Remind Me Later” option causes new problems of deferred security coping behaviors. In other words, hesitant users do not take appropriate actions immediately when security threats take place. Grounding our theoretical basis on choice deferral and dual-task inference, we designed two experiments to understand the key factors affecting users’ deferred security coping decisions in a three-option MSN scenario (“Yes”, “No”, “Remind Me Later”), to determine which MSN message and design features facilitate immediate security coping.