Two-dimensional materials have attracted due to their remarkable optical, electrical, and chemical properties in different crystalline forms. Hexagonal and cubic boron nitride (BN) and their nanostructured forms are compared in respect to their capacitive behavior in different electrolytes. We found that hexagonal BN nanosheets exhibited the highest gravimetric capacitance compared with its bulk and with the cubic BN (bulk and nanosheets) counterpart. The higher capacity originates from the larger surface of nanosized sample and is related to it crystal structure as well. These materials can be beneficial in energy storage applications when forming electrode of supercapacitors, where high energy density is required.