<p>In the present work, stationary points of the Poisson’s ratio for six-constant tetragonal crystals are investigated. For simple cases, analytical expressions for the points and stationary values are provided. The work expands on earlier study: analyzes general case when no strict restrictions applied on loading direction and evaluates crystallographic directions corresponding to stationary points. Using data on elasticity constants, stationary points and values for 94 crystals are determined. Behavior of auxetic crystals investigated for specific crystallographic planes and directions.</p>