The purpose of this mixed methods research study was to investigate how evidence-based adolescent literacy practices are implemented by secondary teachers in the classroom or what the reasons might be for these practices not being implemented. Three secondary English teachers of three different types of classes, comprising Intensive, Project-based Learning and regular curriculum, were interviewed about their knowledge of evidence-based practices and their perceived barriers in implementing them. Their classrooms then were observed for implementation of adolescent literacy practices as defined by the National Council on Teachers of English' Policy Brief on Adolescent Literacy. Finally, students in the classes were surveyed using the Adolescent Motivation to Read Profile (AMRP). Teachers displayed knowledge of evidence-based practices but could not define the term; the closest term in meaning was research-based practices. Teachers also believed they were the final determiner of which practices were successful with their students. Teachers viewed barriers differently according to the class they taught. All of the teachers stated that classes containing more than 30 students and a lack of planning time were barriers. Two of the teachers denoted that technology training was lacking or was out-of-sync with their needs. Teaching is a complex process and implementation of evidence-based practices can be affected by materials chosen and type of class taught, as well as by teachers' beliefs that those practices will be successful with their students. All of the teachers actively sought out evidence-based practices for their classrooms. Additional observations could increase the number of practices applied by each teacher. Administrative personnel control the barriers of class size, technology training, and adequate time for planning. There was no statistically significant difference in the scores for the AMRP survey in Self-concept and Reading Value among the three class types. A potential reason might be that students in the Intensive classes have more choices and are receiving instruction that increases their motivation. Students for the Project-based Learning class were randomly assigned; therefore, the element of choice was removed. A definition of reading was not provided prior to the scoring and because the protocol was self-rated, caution should be used in the comparisons. [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/en-US/products/dissertations/individuals.shtml.]