Lake Forest High School, or LFHS, is a public four-year high school located in Lake Forest, Illinois, a North Shore suburb of Chicago, Illinois, in the United States. It is the only school of Lake Forest Community High School District 115, which serves the communities of Lake Forest, Lake Bluff, Knollwood, and smaller parts of Mettawa and North Chicago. It is fed by Lake Bluff Middle School, Lake Forest Country Day School, Saint Mary's, and Deer Path Middle School.

The North Shore consists of many affluent suburbs north of Chicago, Illinois, bordering the shores of Lake Michigan. These communities fall within suburban Cook County and Lake County. The North Shore's membership is often a topic of debate, and it includes some Chicago suburbs which do not border Lake Michigan. However, Lake Bluff, Lake Forest, Highwood, Highland Park, Deerfield, Glencoe, Northbrook, Northfield, Winnetka, Kenilworth, Wilmette, Golf, Glenview, Niles, Morton Grove, Skokie, and Evanston, are generally considered to be the main constituents of the North Shore. The North Shore is known for its affluence, high level of education, proximity to Chicago, and top-rated public schools.