Lead halide perovskites, particularly those with the formula APbX₃, are extensively studied for their potential in photovoltaic applications. Mixing different ions in these materials enhances their stability and performance. This review summarizes the effects of mixing on the structural and dynamic properties of three- and low-dimensional lead halide perovskites. It discusses structural phase transitions, crystal symmetry, cation and lattice dynamics, and phase diagrams. The review analyzes various mixing strategies and their impact on the material's properties. It covers structural phase transitions in nonmixed 3D perovskites, mixing effects at A-, X-, and B-sites, and the behavior of low-dimensional perovskites. The review also highlights the importance of understanding mixing effects for improving the performance and stability of these materials in photovoltaic and other applications. Key findings include the role of mixing in stabilizing cubic phases, tuning optical and electronic properties, and enhancing stability. The review emphasizes the need for a systematic understanding of mixing effects to advance the development of lead halide perovskites for practical applications.Lead halide perovskites, particularly those with the formula APbX₃, are extensively studied for their potential in photovoltaic applications. Mixing different ions in these materials enhances their stability and performance. This review summarizes the effects of mixing on the structural and dynamic properties of three- and low-dimensional lead halide perovskites. It discusses structural phase transitions, crystal symmetry, cation and lattice dynamics, and phase diagrams. The review analyzes various mixing strategies and their impact on the material's properties. It covers structural phase transitions in nonmixed 3D perovskites, mixing effects at A-, X-, and B-sites, and the behavior of low-dimensional perovskites. The review also highlights the importance of understanding mixing effects for improving the performance and stability of these materials in photovoltaic and other applications. Key findings include the role of mixing in stabilizing cubic phases, tuning optical and electronic properties, and enhancing stability. The review emphasizes the need for a systematic understanding of mixing effects to advance the development of lead halide perovskites for practical applications.