This research investigated whether music performance anxiety (MPA) can be theoretically understood as a unidimensional construct, and whether the factorial structure is robust across different populations of musicians with different levels of expertise. K-MPAI scores were obtained from 455 Peruvian tertiary music students (mean age = 21.19 years, SD = 3.13, range = 18–40 years) and 368 Australian professional orchestral musicians (mean age = 42.07 years, SD = 10.21, range = 18–68 years). A high order exploratory factor analysis with the Schmid-Leiman solution was performed on the K-MPAI items. Unweighted Least Squares extraction method and optimal implementation of parallel analysis revealed one high order factor and two first order factors for both samples. High Cronbach’s and ordinal alpha levels for items belonging to each first order and high order factor in both samples were also obtained. Structural similarities between the two samples and an invariance analysis signified a comparable structure and conceptual interpretation of K-MPAI scores in both populations. The factorial structure obtained supported a unidimensional interpretation of the construct of MPA. First order level interpretations are also possible and have been demonstrated to be clinically useful.