Are there any significant differences in attitudes toward professional development among lower elementary, upper elementary, middle school, and secondary teachers in public schools in San Juan, Puerto Rico, District II? Do participants of different demographic characteristics (age, gender, subject(s) taught, years of teaching experience, and level of educational attainment) have significant differences of attitudes toward professional development? This study examined quantitatively the differences of attitudes of teachers (N=166) from different grade spans toward PD, with consideration given to demographic characteristics, and provided a comparison between the contexts of teachers. The historical analysis and results of the study can assist educational leaders in making profound decisions to impact teaching and learning, not just for Puerto Rico's public schools, but for any educational institution.