The robbery was reported at about 3:40 a.m. Sunday in the 900 block of Florida Street.
The victim, a 45-year-old man, had just gotten out of his car to deliver the pizza when he was approached by three men, one of whom punched him in the face, according to police.
The other two rifled through his pockets, taking cash and a cellphone. One then got into the victim's truck, a 1999 gold Toyota Tacoma, and drove away in it, police said.
The suspects and the truck had not been found as of Monday morning.
The victim did not need to be taken to a hospital.
Anyone with information about the robbery is encouraged to call the Police Department's anonymous tip line at (415) 575-4444 or send a tip by text message to TIP411.