The school colors of crimson and cream became official over a century ago and you can still see those colors worn proudly by Sooner athletes and fans alike on gamedays or when they want to show their love for the university.
In the fall of 1895, Miss May Overstreet was asked to chair a committee to select the colors of the university. The committee decided the colors should be crimson and cream and an elaborate display of the colors was draped above a platform before the student body.
The student body approved with great enthusiasm and immediately pennants, banners, badges and decorations of every description appeared on the streets, in the windows, at chapel, in classrooms, and all public places; however, local merchants could not supply the demand.
Even though the school colors have evolved to crimson and white over the years, you can ask any self-respecting Sooner what the colors are and they will proudly announce "Crimson and Cream." 
On gamedays, a sea of crimson rolls through OU's home arenas and all Sooners are urged to wear the official colors to show the rest of the country what school spirit and Sooner Pride are all about.