and light-weight SCs with the capability of being rolled-up have fascinated particular interest in wearable and portable electronics as a next-generation power system. [4] To design these devices, textilebased electrodes with well-architectured nanomaterials are crucial. [5] Accordingly, several textile-based substrates which include carbon cloth, carbon nanotube coated fabric, carbon fiber paper, etc. have been explored for flexible SCs owing to their intertwined fibrous texture, high flexibility and excellent stability. [6] In fact, the carbon-based textiles/papers suffer from high hydrophobicity and low conductivity, and they are not suitable for clothing. Meanwhile, in view of the cost, the carbon textile/paper-based electrodes are expensive and the complicated process could be required to attain these substrates. [7] Therefore, it is important to pursue suitable alternatives with low cost and ecofriendliness for carbon-based textiles. [8,9] In this context, the conductive fabrics (CFs) which are fabricated with a simple wet-chemical-based plating of metallic layers on polyester fibers enable the prominence in several textile industries. [10] Such chemical-based coating methods can be easily scaled up for low-cost and large-scale production. [11] As a result of the strongly adhered metallic layers on polyester fibers, they can easily lift up the CFs for desirable properties including high conductivity, great flexibility, high mechanical stability and water washability. The attractive properties of CFs offer great potential for flexible electrodes in SCs.On the other hand, the recent development of nanomaterials and nanotechnology has enabled the advanced electroactive materials for high-performance SCs. Typically, SCs may store energy through two mechanisms which include electric double-layer capacitive (EDLC) process and faradaic redox reaction. [12,13] Because of the higher discharge capacity and multiple oxidation states, faradaic electroactive materials show higher electrochemical performance than EDLC materials. So far, transition metal hydroxide/oxides including Co(OH) 2 , ZnCo 2 O 4 , CuO, NiO, CoMoO 4 , NiCo-layered double hydroxide (LDH), etc. with versatile morphologies were investigated mainly as redox-active materials. [11,[14][15][16] However, the rate performance and stability of these transition metal hydroxides/oxides are still inferior because of their poor electrical Highly flexible and conductive fabric (CF)-supported cauliflower-like nickel selenide nanostructures (Ni 3 Se 2 NSs) are facilely synthesized by a singlestep chronoamperometry voltage-assisted electrochemical deposition (ECD) method and used as a positive electrode in supercapacitors (SCs). The CF substrate composed of multi-layered metallic films on the surface of polyester fibers enables to provide high electrical conductivity as a working electrode in ECD process. Owing to good electrical conductivity, high porosity and intertwined fibrous framework of CF, cauliflower-like Ni 3 Se 2 NSs are densely integrated onto the ent...