Novel silicone pressure-sensitive adhesives containing modified montmorillonite were obtained, and subsequently, one-sided tapes were prepared. The novel adhesives were characterized by a higher tack, peel adhesion, and cohesion at room and elevated temperature when compared to the system without the filler. Adding modified fillers allowed to improve the thermal resistance of adhesive - the maximum operating temperature was in a range of 220–230 °C. The highest level of thermal resistance was obtained for acid-modified montmorillonite with a concentration of 0.1 M. It was found that the physical modification of silicone pressure-sensitive adhesives shifts the adhesive-cohesive balance towards cohesion.