Despite accumulated knowledge of the role of self-concealment on various personal and relational problems, there are limited empirical attempts to highlight the possible precursors of this pattern. The current study investigated the mediator role of emotion regulation (ER) difficulties in the association between psychological needs satisfaction and self-concealment. The data was collected from 480 volunteer university students aged between 18 and 30 (M = 21.55, SD = 2.00). Self-report questionnaires were administered online, including The Difficulties in Emotion Regulation Scale-Brief Form, Self-Concealment Scale, and Basic Psychological Needs Scale-Revised Form. The correlation analysis revealed that basic need dissatisfaction was positively correlated with ER difficulties and a tendency to keep oneself in the dark. Then, regression analysis confirmed that ER difficulties had a full mediator role in the association between unmet needs and self-concealment. Accordingly, decreased need satisfaction contributed to the tendency to keep secrets through greater difficulty in regulating emotions. Current findings suggest an explanation for developing the motivation to hide personal information from others within the Self-Determination Theory framework. The role of difficulty in emotion regulation contributes to conceptualizations of psychological and relational problems, highlighting the significance of considering emotion regulation skills in prevention and treatment practices.