This chapter of the ATLAS Detector and Physics Performance Technical Design Report focuses on the ability of the ATLAS detector at the CERN LHC to search for and make precision measurements of Supersymmetry (SUSY). The primary emphasis is on detailed studies of selected points in the minimal supergravity model, the minimal gauge-mediated SUSY breaking model, and R-parity violating models. The chapter discusses the motivation for studying SUSY, the particle content and interactions of SUSY particles, and the solutions to the hierarchy problem that SUSY provides. It also covers the phenomenological implications of SUSY breaking, including the cancellation of quadratic divergences in scalar masses and the requirement of gauge invariance and renormalizability. The chapter then delves into the minimal Supersymmetric Standard Model (MSSM), explaining the mixing of chiral fermions and their superpartners, as well as the mixing of gauginos and Higgsinos. It discusses the phenomenological consequences of SUSY breaking, such as the production of lightest SUSY particles (LSP) and the signatures of different SUSY models. The chapter also provides an overview of the experimental techniques used to search for SUSY, including inclusive and exclusive measurements. It details the selection criteria for various SUSY signatures, such as jets, missing transverse energy, and dileptons, and the background estimation methods. The chapter highlights the reach of these searches in different SUSY models and the precision with which SUSY masses can be measured. Finally, the chapter presents detailed analyses for five selected points in the minimal SUGRA model, demonstrating how to reconstruct SUSY particles and extract their masses from kinematic endpoints of distributions. It discusses the sensitivity of these measurements to SUSY parameters and the potential for distinguishing different SUSY models.This chapter of the ATLAS Detector and Physics Performance Technical Design Report focuses on the ability of the ATLAS detector at the CERN LHC to search for and make precision measurements of Supersymmetry (SUSY). The primary emphasis is on detailed studies of selected points in the minimal supergravity model, the minimal gauge-mediated SUSY breaking model, and R-parity violating models. The chapter discusses the motivation for studying SUSY, the particle content and interactions of SUSY particles, and the solutions to the hierarchy problem that SUSY provides. It also covers the phenomenological implications of SUSY breaking, including the cancellation of quadratic divergences in scalar masses and the requirement of gauge invariance and renormalizability. The chapter then delves into the minimal Supersymmetric Standard Model (MSSM), explaining the mixing of chiral fermions and their superpartners, as well as the mixing of gauginos and Higgsinos. It discusses the phenomenological consequences of SUSY breaking, such as the production of lightest SUSY particles (LSP) and the signatures of different SUSY models. The chapter also provides an overview of the experimental techniques used to search for SUSY, including inclusive and exclusive measurements. It details the selection criteria for various SUSY signatures, such as jets, missing transverse energy, and dileptons, and the background estimation methods. The chapter highlights the reach of these searches in different SUSY models and the precision with which SUSY masses can be measured. Finally, the chapter presents detailed analyses for five selected points in the minimal SUGRA model, demonstrating how to reconstruct SUSY particles and extract their masses from kinematic endpoints of distributions. It discusses the sensitivity of these measurements to SUSY parameters and the potential for distinguishing different SUSY models.