The purpose of this study was to investigate high school English teachers' perception and practice of critical thinking skills in their classrooms in developing the critical thinking abilities of the senior high level students in Edmonton schools. The intent was to discover if high school English teachers realize the importance and the great significance of thinking critically, and if they modeL, practice and implement it through their teaching methods, to develop the students' critical thinking skills. -- The data concerning teachers' perceptions and beliefs on critical thinking were gathered through interviews conducted with eight English teachers for Grades 10, 11 and 12, in six different schools in Edmonton, Alberta. These interviews were recorded on audio-cassette, transcribed, and analyzed to reach an understanding and a conclusion. The data concerning teacher-student classroom verbal interaction was collected through in-class observation of one or two classes for each teacher either before or after the interviews. -- The findings of this study indicated that critical thinking continues to grow in popularity. Most of the high school English teachers realize and believe in the value of critical thinking as an academic competency that is crucial for the students' future success and progress. Most high school English teachers practice and model these skills to their students, and try to creatively develop the students' critical thinking skills. There are many opportunities in the high school English curriculum for educators to help develop critical thinking skills. The study revealed that the integration of critical thinking skills through the creative and effective use of various teaching methods is possible and essential. A significant finding was that high school English teachers can be highly influential in establishing a classroom environment that fosters critical thinking development.