The Src family tyrosine kinase Fyn regulates a myriad of neurophysiological processes, including learning and memory. To date, the role of Fyn in the neurological mechanisms that determine personality traits has not been addressed. To this end, we determined the association between the rs706895C/T polymorphism of the Fyn gene (FYN) and personality traits measured by the Tridimensional Personality Questionnaire in 502 healthy Chinese-Han subjects. There were no significant differences in the total scores for novelty seeking (χ² = 5.12, P = 0.077), harm avoidance (HA; χ² = 2.63, P = 0.269), or reward dependence (RD; χ² = 3.94, P = 0.139) among the rs706895C/T genotypes. In sub-item analyses, however, both fear of uncertainty (HA2; χ² = 7.84, P = 0.020) and sentimentality (RD1; χ² = 8.27; P = 0.016) scores were significantly different among rs706895C/T genotypes. Our results suggest that FYN alleles can contribute to the variance in human personality traits.