The purpose of this quantitative correlational research study was to determine to what extent, if any, teacher technology-related professional development affected the actual integration of technology in the classroom among 9th-12th-grade teachers. Convenience sampling was used to collect data. The sample for this study was 78 high school teachers from four high schools in a school district in south Texas, USA. The Technology Acceptance Model (TAM) and the Technological Pedagogical Content Knowledge (TPACK) were used for the theoretical framework. The multiple linear regression analysis addressed three research questions. Research question one asked whether the set of technology factors predict the level of technology integration in classroom instruction by high school teachers. The results showed no statistically significant relationship between the variables F(2, 71) = 1.75, p = 0.18). Research question two asked to what extent does the number of professional development opportunities predicts teacher level of technology integration in classroom instruction. The results showed no statistical significance (B = 0.05, F(1,72), p = 0.07). Research question three, which also showed no statistical significance (B = -0.004, p = 0.82), asked to what extent do hours spent on technology-related professional development activities predict teacher level of technology integration in classroom instruction. The results of the study revealed that professional development did not help teachers integrate technology into their classroom instruction. Keywords: quantitative, correlational, technology, professional development, education, TAM, TPACK. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]