Davis said Monday the Dallas dentist shares her commitment to creating jobs and improving public education.
Alameel is one of five candidates seeking the Democratic nomination on March 4. Incumbent Republican Sen. John Cornyn faces six challengers in the Republican primary.
Davis is running for governor and her endorsement will likely make Alameel the front-runner in the Democratic primary. Last year Alameel ran for a new congressional seat in the metroplex, losing to Democratic U.S. Rep. Marc Veasey.
The U.S. Army veteran thanked Davis for her support and promised that if elected he will fight to protect Medicare and Social Security.
No Democrat has won a statewide election since 1994.