P. pacificus may refer to:
Pristionchus pacificus, a free-living nematode Polistes pacificus, a neotropical paper wasp Palaemon pacificus, a species of shrimp Parazen pacificus, an Atlantic zeiform fish Paraconcavus pacificus, an acorn barnacle Pelagihabitans pacificus a marine bacterium Philanthus pacificus, another species of New World wasp Profundiconus pacificus, a species of sea snail Peregocetus pacificus, an early form of whale discovered in Peru Paraletharchus pacificus, the sailfin eel Porribius pacificus, the New Zealand bat flea