William Wright Baldwin, president of the South End Land Company, founded Bellaire in 1908 on part of the 9,449-acre ranch once owned by William Marsh Rice, benefactor of Rice Institute (now Rice University). Baldwin surveyed the eastern 1,000 acres of the ranch into small truck farms, which he named Westmoreland Farms. He platted Bellaire in the middle of the farms to serve as an exclusive residential neighborhood and agricultural trading center. The project was separated from Houston by approximately six miles of prairie. South End Land Company advertisements, targeted to midwestern farmers, noted that Bellaire ("Good Air") was named for the area's Gulf breezes. The original townsite was bounded by Palmetto, First, Jessamine, and Sixth (now Ferris) streets. Bellaire Boulevard and an electric streetcar line connected Bellaire to Houston. The town was incorporated in 1918, and C. P. Younts served as first mayor.
The post-war building boom in the late 1940s and early 1950s resulted in rapid population growth. Completely surrounded by the expanding city of Houston by 1949, Bellaire nevertheless retained its independence and its own city government.