<p>Halide perovskites are promising photovoltaic materials, but their mechanical properties, which are critical for the stability in service conditions, are less reported. Here, we systematically study the elastic, plastic, fracture, and creep properties of various halide perovskite single crystals, including inorganic CsPbBr₃, organic–inorganic hybrid FAPbBr₃, mixed-cation FA_0.9Cs_0.1PbBr₃, and a perovskite analog (C₅H₁₆N₂)Pb₂I₆, of their growth-preferred orientations using nanoindentation. Our results show that halide perovskite single crystals exhibit low Young’s modulus and nanohardness, and organic–inorganic hybrid perovskites are brittle. This work provides a thorough investigation and discussion of the mechanical properties of halide perovskite single crystals and the structure–mechanical property relationships.</p> Graphical abstract <p></p>