Halladay (13-8) allowed four hits and one run while striking out eight, winning for the fifth time in seven starts.
Bobby Crosby's homer was the lone offense for the Athletics, who have lost seven in a row and 10 of 11.
Losing pitcher Sean Gallagher (1-1) allowed five runs on four hits over three innings.
Ray Liotta sues skin care company over use of likeness
Aaron Carter is still in love with Hilary Duff