FM 149 was created on April 20, 1945 as a short spur between Anderson and Richards inside Grimes County. Later that year, it was extended twice, to the Montgomery County line on June 6, 1945 and to Deckers Prairie ten days later. The designation was extended down the Tomball Road to US 75 (later  I-45) in Houston on July 22, 1949.
FM 149 was established on April 20, 1945 as a brief offshoot between Anderson and Richards within Grimes County. Subsequently that year, it was expanded twice, to the Montgomery County boundary on June 6, 1945 and to Deckers Prairie ten days later. The designation was extended along Tomball Road to US 75 (later I-45) in Houston on July 22, 1949.