Mark Thackeray is a fictional character from the 1967 film "To Sir, with Love," portrayed by actor Sidney Poitier. He is a dedicated teacher who takes a job at a troubled school in London's East End, where he faces challenges with a group of unruly students. Thackeray's approach to education emphasizes respect, understanding, and personal growth, making a significant impact on his students' lives. The film explores themes of social issues, race, and the importance of education. Thackeray's character is known for his patience and innovative teaching methods, which help bridge the gap between him and his students, ultimately fostering a sense of community and mutual respect.