An apparatus for an adhesive tape dispenser/applicator is disclosed. The adhesive tape dispenser/applicator includes an ergonomically shaped housing and tape applicator/cutter assembly that permits one-handed dispensing of pressure sensitive adhesive tape from a roll while simultaneously applying the tape to a substrate. The adhesive tape dispenser/applicator allows all operations to be performed single-handedly, and without the user ever having to directly touch the tape. In addition, there is no need to pre-measure or estimate the length of tape needed as the desired length of tape is dispensed as it is being applied to the substrate.