AbstractLayered Li₂SrNb₂O₇, an inorganic oxide in its bulk single‐crystalline form, is experimentally demonstrated to exhibit multiple structural facets such as ferroelasticity, ferroelectricity, and antiferroelectricity. The transition from a room temperature (RT) centrosymmetric structure to a low‐temperature out‐of‐plane ferroelectric and in‐plane antiferroelectric structure and the low‐temperature (LT) ferroelectric domain configuration are unveiled in TEM, piezoresponse force microscopy, and polarization loop studies. Li₂SrNb₂O₇ also exhibits highly tunable ferroelasticity and excellent Li⁺ in‐plane conduction, which leads to a giant in‐plane memristor behavior and an in‐plane electronic conductivity increase by three orders of magnitude by electric poling at room RT). The accumulation of Li⁺ vacancies at the crystal–electrode interface is visualized using in situ optical microscopy. The Li‐ionic biased state shows a clear in‐plane rectification effect combined with a significant relaxation upon time at RT. Relaxation can be fully suppressed at LTs such as 200 K, and utilizing an electric field cooling, a stable rectification can be achieved at 200 K. The results shed light on the selective control of multifunctionalities such as ferroelasticity, ferroelectricity, and ionic‐migration‐mediated effects (a memristor effect and rectification) in a single‐phase bulk material utilizing, for example, different directions, temperatures, frequencies, and magnitudes of electric field.