The current research constructs a measure of one's willingness to form online relationships and disclose personal and private information and examines how this measure relates to personality and individual differences. In Study 1, we developed a measure to assess one's Openness to Form Online Relationships (OFOR). Two factors emerged: Engagement and Suspicion. Results indicated that individuals who reported higher OFOR Engagement also self‐reported higher self‐concealment and self‐monitoring and lower Honesty‐Humility and Conscientiousness. In Study 2, we examined the extent to which our measures and the OFOR related to people's actual willingness to share personal information. Higher OFOR Engagement was related to greater disclosure. In addition, self‐concealment and the Dark Triad were significantly related to the severity and privacy of self‐disclosure. The current research constructs a new measure of and provides insight into some of the individual differences and personality traits involved in a person's openness to form relationships online and his/her willingness to disclose private information. This work contributes to our understanding of the factors that may make some individuals vulnerable to being deceived by others in the online environment. This work can be used to inform training or messaging to increase community resilience against deception, such as online scams.