The purpose of this study was to investigate the relationships between music training and musical complexity and focus of attention to melody or harmony. Participants (N = 192) were divided into four groups: university jazz majors (n = 64), other university music majors (n = 64), high school instrumentalists (n = 32), and junior high instrumentalists (n = 32). The musical complexity variable consisted of four levels of melodic complexity and four levels of harmonic complexity each paired for a total of 16 possible combinations all heard by each participant. Each trial consisted of a melodic complexity/harmonic complexity pairing performed by the same performer on jazz piano. Subjects indicated their overall perceived focus of attention for melody or harmony either during or immediately after they listened. A four-factor ANOVA was conducted with two between-subjects factors (order and music-training groups) and two within-subjects factors (melodic complexity and harmonic complexity). Significant differences were found for focus of attention for both melodic complexity and harmonic complexity. Significant interactions occurred between music training and focus of attention. Overall, data showed that as music training increases, so does harmonic focus of attention. (Contains 1 table and 2 figures.)