The necessity of benefiting a breakthrough in filtration technology has led to increasing attention in advanced functional nanosized materials such as nanofibers for filtering devices as a solution for providing water at lower energy costs. In this study, electrospun polyacrylonitrile (PAN) nanofibrous membranes were reinforced by 1, 2, and 3 w/w of halloysite nanotubes (HNTs) in order to improve their mechanical properties, thermal stability and water filtration performance for the possible application as water filtration membranes. Morphological analysis revealed the highly porous and nanofibrous structure of membranes which further confirmed by surface area analysis (BET). Incorporation of HNTs enhanced the mechanical properties of the membranes such as tensile strength and elongation at break (especially at 1 w/w HNTs) while resulted in significant improvement of their thermal properties. Moreover, PAN/HNTs membranes showed excellent oil/water separation performance, while incorporation of HNTs led to increase in water flux rate, which is considered as a key point in water filtration membranes. Additionally, heavy metal ion adsorption performance of the membranes showed a significant increase by incorporation of 3 w/w HNTs. These results signified the potential of electrospun PAN/HNTs nanofibrous membranes to be used for water filtration applications.