Two-dimensional (2D) materials have the advantages of possessing reactive and tunable in-plane or surface properties that are absent in other types of materials [1]. Single 2D Ti3C2Tx nanosheets, commonly known as MXenes, have unique inherent properties, such as exceptional metal-like conductivity, high electrical and electrochemical properties, as well as a reactive surface that can be processible in various solvents [2-3]. The self-assembly of these 2D nanomaterials can be useful in the formation of micro- and macro-architectures, such as the formation of fibres [4]. However, most 2D nanomaterials also have unavailable specific intermolecular interactions for these spontaneous assemblies that can make it difficult to induce and control the self-assembly process [5]. In this study, control of the self-assembly of MXene dispersions was investigated for its application in fibre wet-spinning processes. The control of the MXene self-assembly was achieved through the addition of different types of acidic solutions that can promote the interfacial interactions between single sheets by introducing positive H+ species to the negatively-charged MXene surface. Using X-ray Photoelectron Spectroscopy (XPS), the surface chemistry variations as an effect of acid treatment was investigated. We found the Ti–O and C–Ti–OH bonds increased in concentration due to the abundant H+ in the acid-treated MXene compared to the pristine dispersions. Small- and Wide-Angle X-ray Scattering (SAXS/WAXS) techniques was also utilized to measure the inter-sheet d-spacing and degree of orientation both for the MXene in dispersions and in fibre form. We measured similar d-spacing values for the pristine and acid-treated MXene dispersions, suggesting that the H+ may not be intercalated within the single MXene sheets. However, there is a transition from isotropic to anisotropic alignment of the acid-treated MXene sheets in dispersion, which suggest an increased sheet orientation and interfacial interactions. The MXene fibres produced using the acid-treated dispersions were also measured to have a higher degree of orientation (OI) of 0.79 compared to the control fibres (OI = 0.61). The improved sheet alignment also translate to better overall fibre performance with a significant increase in the tensile strength of the highly oriented fibres. Here, we demonstrated the control of the self-assembly of 2D MXene sheets allows for the fine tuning of the macroscopic fibre architecture to improve its overall properties. This technique can also be utilized in other 2D nanomaterials with reactive surfaces and can be used in the rational design of other types of macrostructures for various research and industrial applications.