Objective: Traits defined by the Five-Factor Model (FFM) of personality have been linked to physical health, leading to treatment implications and psychophysiological conceptualizations. Previous studies have reported a consistent link between neuroticism and asthma. This study aims to reinforce this finding and further its scope by looking at all five personality traits and lifetime asthma diagnosis. Methods: The current study examined associations between personality traits and lifetime asthma diagnosis in a sample of 3993 participants and, for the purposes of replication, a second sample of 1692 participant siblings. Personality was measured at a single time point in adulthood (mean age: 53 years), while asthma diagnosis by a medical professional was self-reported across three time points over a range of 54 years. A binary logistic regression was performed to examine the association between FFM personality traits and the likelihood of having endorsed asthma at any time point. Results: Higher scores in the traits of neuroticism (beta = 0.024, p = .03, OR = 1.025) and openness (beta = 0.041, p < .001, OR = 1.042) were associated with increased risk of lifetime asthma diagnosis, while the trait of conscientiousness (beta = -0.034, p = .009, OR = 0.967) was associated with decreased risk of lifetime asthma diagnosis. The associations with neuroticism and openness were replicated in the sibling sample. Conclusion: These findings suggest that research into certain personality traits might help us better understand psychophysiological connections. Neuroticism, openness, and conscientiousness might be salient factors in developing asthma education and treatment.