The invention provides seed and plants of tomato line PSQ 23-2278. The invention thus relates to the plants, seeds and tissue cultures of tomato line PSQ 23-2278, and to methods for producing a tomato plant produced by crossing such plants with themselves or with another tomato plant, such as a plant of another genotype. The invention further relates to seeds and plants produced by such crossing. The invention further relates to parts of such plants, including the fruit and gametes of such plants.