This paper analyzes the performance of space shift keying (SSK) modulation for a generic multipleinput multiple-output (MIMO) wireless system operating over generalized κ − μ fading channels. In particular, an expression of the pair wise error probability (PEP) is obtained. In addition, simple and general asymptotic expression for the PEP is given. The derived expression for the PEP is general, such that the PEP over various well-known fading channels can be derived as special cases, such as Nakagami-m and Nakagami-n (Rice) fading channels. Numerical results are provided, sustained by simulation results, which corroborate the exactness of the theoretical analysis. Key–Words: Amplify-and-forward, Quadrature spatial modulation, Spectral efficiency, MIMO.