<p dir="ltr">Fearlessness is a construct often discussed in clinical and personality psychology. However, at the self-report trait level, there is little work focusing on its empirical structure and how that applies to measurement. The present study examined the IPIP-Fearlessness scale using experience sampling methodology to examine how scores on the measure predict behaviors in daily life. Using a pre-registered analytical approach, participants completed a baseline survey and brief daily surveys six times daily for one full week. The final sample consisted of 241 participants. Criterion variables measuring boldness, general personality, sensation seeking, and sensitivity to reward and punishment were also correlated with the IPIP-Fearlessness measure’s subscales, and a confirmatory factor analysis confirmed the measure’s structure.</p><p dir="ltr">Results showed that two of the IPIP-Fearless subscales (Low Anxiety and Sociability) did predict daily behaviors, whereas there were not significant predictions found for the other behaviors. Affect (negative, positive, anxious, bored) was also found to be significant predictor for several of the behavioral outcome variables, as well as interpersonal status. Additional exploratory analyses were also conducted. The findings from this study continue to elucidate how we can use empirically derived self-report trait fearlessness, and its relationship to additional constructs and behaviors.</p>