A printing fluid cartridge a printing fluid cartridge is configured to be inserted into a printing fluid consuming apparatus in an insertion direction. The printing fluid cartridge includes: a storage chamber, a supply portion, a rear surface, an upper surface, an electrical interface, a locking surface, one protrusion, and another protrusion. The storage chamber is configured to store printing fluid. The one protrusion and the another protrusion define a plurality of imaginary planes each of which passes through the one protrusion and the another protrusion. The plurality of imaginary planes includes a specific imaginary plane. The specific imaginary plane is positioned higher than any other imaginary plane between the one protrusion and the another protrusion. The electrical interface is positioned downward relative to the specific imaginary plane in the gravitational direction in the attached posture.