The purpose of this quantitative study was to investigate the effects of using Twitter within the classroom on a secondary level and to determine whether the use of Twitter had statistically significant effects on student engagement and academic performance. Engagement is applied to student learning using Kearsley and Shneiderman's (1998) engagement theory and Kolb's (2015) experiential learning theory. This quasi-experimental study focused on four secondary level science classes during one marking period of the school year (45 school days). Eighty-seven students took part in the study. The control group participated in class as regularly scheduled. The treatment group was subject to using Twitter in the classroom to measure a potential change in student engagement. Both the control group and the treatment group were exposed to the same biology curriculum, assessments, and assignments throughout the 45-day marking period. Neither educator had used Twitter prior to this research. Students were encouraged by the classroom educators during class to use Twitter as a means of participation. Pretest and posttest surveys were administered to students in both groups consisting of questions related to technology use and student engagement as determined by the High School Survey of Student Engagement (HSSSE, 2013). Results were determined using descriptive statistics, paired-sample t-tests, and mixed ANOVA. The effect of Twitter on student engagement was determined to be statistically significant; however, the effect of Twitter on academic performance was not found to be statistically significant. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]