The disclosure relates to a cotton variety, designated 11PNFS45, the plants and seeds of the cotton variety 11PNFS45, methods for producing a cotton plant, either varietal or hybrid, produced by crossing the cotton variety 11PNFS45 with itself or with another cotton plant, hybrid cotton seeds and plants produced by crossing the variety 11PNFS45 with another cotton variety or plan, methods for producing a cotton plant containing in its genetic material one or more transgenes, and the transgenic cotton plants produced by that method. This disclosure also relates to cotton varieties derived from cotton variety 11PNFS45, to methods for producing other cotton varieties derived from cotton variety 11PNFS45, and to the varieties derived by the use of those methods.