This study concerns with the preparation of flame retardant and hydrophobic cellulosic fabric by using hexagonal boron nitride nanosheets (h-BNNs). h-BNNs were prepared from hexagonal boron nitride (h-BN) using two different exfoliation methods. These methods include direct sonication (aq-BNNs) and sonication after pretreatment with Hummers method (Hum-BNNs) in aqueous medium. The characterization of h-BNNs was carried out by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), limited oxygen index (LOI), and water contact angle (WCA) analysis. The surface morphologies of h-BNNs were investigated via atomic force microscope (AFM). The coating with the h-BNNs was proved by scanning electron microscopy (SEM). Hummers method is considered to be more effective reaction by gained functionality to h-BN structure. In this way, it will easily provide physical or chemical interaction between the functionalized h-BN and cellulosic structure. A nanometric-sized large layers and slightly functionalized h-BNNs were obtained using Hummers method. Hum-BNNs dispersions were sprayed onto the surface of cellulosic tent fabric to show flame retardance properties. However, it was observed that the flame retardant effect of nanolayered h-BNNs prepared by both methods were insufficient. In addition, ultrahydrophobic surfaces were almost obtained using aq-BNNs and Hum-BNNs. It was conclusively proposed that a few amounts of Hum-BNNs can be used as hydrophobic coating for cellulosic fabric surface with this way.