The off-centering effect in thermoelectric materials refers to the displacement of constituent atoms from their coordination centers, leading to local structural distortion and symmetry breaking while maintaining overall crystallographic symmetry. This phenomenon significantly reduces thermal conductivity by introducing low-frequency optical phonon modes and enhancing acoustic-optical (A–O) phonon scattering, which is crucial for improving thermoelectric performance. The off-centering effect is driven by factors such as lone pair electrons, weak electronic orbital hybridization, oversized coordination environments, and weak chemical bonding. It has been observed in various thermoelectric materials, including PbTe, AgGaTe₂, and halide perovskites, and has been shown to effectively lower thermal conductivity, making these materials promising for thermoelectric applications. The off-centering effect can be induced not only in intrinsic materials but also through doping with discordant atoms, such as Ag, Cd, and Hg in PbSe. This effect provides a new strategy for designing high-performance thermoelectrics by regulating thermal conductivity and enhancing thermoelectric efficiency. Understanding the mechanisms behind the off-centering effect is essential for developing advanced thermoelectric materials with improved energy conversion efficiency.The off-centering effect in thermoelectric materials refers to the displacement of constituent atoms from their coordination centers, leading to local structural distortion and symmetry breaking while maintaining overall crystallographic symmetry. This phenomenon significantly reduces thermal conductivity by introducing low-frequency optical phonon modes and enhancing acoustic-optical (A–O) phonon scattering, which is crucial for improving thermoelectric performance. The off-centering effect is driven by factors such as lone pair electrons, weak electronic orbital hybridization, oversized coordination environments, and weak chemical bonding. It has been observed in various thermoelectric materials, including PbTe, AgGaTe₂, and halide perovskites, and has been shown to effectively lower thermal conductivity, making these materials promising for thermoelectric applications. The off-centering effect can be induced not only in intrinsic materials but also through doping with discordant atoms, such as Ag, Cd, and Hg in PbSe. This effect provides a new strategy for designing high-performance thermoelectrics by regulating thermal conductivity and enhancing thermoelectric efficiency. Understanding the mechanisms behind the off-centering effect is essential for developing advanced thermoelectric materials with improved energy conversion efficiency.