Developing advanced sorbent materials for effective removal of organic pollutants from water is of critical importance for environmental and water source protection. Here we reported the facile synthesis of hexagonal boron nitride (h-BN) fibers for efficient removal of methylene blue (MB) from water. The h-BN fibers was prepared by a combined sol–gel and temperature-controlled pyrolysis procedure in a N2 atmosphere, using boron acid and melamine as the precursors. The as-prepared fibers showed long fibrous morphology (from several to tens of micrometers), high specific surface area (∼627m2/g), mesoporous (3–4nm) structure. Benefiting from these advantageous features, the resulting h-BN fibers exhibited a fast adsorption rate for MB (C/C0<9% within 10min), a large adsorption capacity of ∼631mg/g, high separation selectivity that can fast adsorb MB from a mixed aqueous solution of MB and CuSO4, easy regeneration by simple heating in air, and excellent recyclability. These results demonstrate the great potential of mesoporous h-BN fibers for water purification and treatment.