A new six parameter general anisotropic yield surface using a fourth order anisotropic tensor Mijkl has been proposed. This form has been derived based on the physical behavior observed for the material under consideration — directionally reinforced metal matrix composites. Its validity has been shown by proving its convexity and form under coordinate transformation. This form of the anisotropic yield function is general in nature which can be used for either pressure dependent or independent cases. By applying suitable conditions on the parameters, it can be reduced to the von-Mises and Tresca isotropic yield criteria. It can also be reduced to specific anisotropic models such as Hill's [1948 “A Theory of the Yielding and Plastic Flow of Anisotropic Metals,” Proceedings of Royal Society of London, A193, 281–297] pressure independent anisotropic yield function form and the Mulhern, Rogers and Spencer [1967 “A Continuum Model for a Fiber Reinforced Plastic Material,” Proceedings of Royal Society of London, A301, 473–492] pressure independent yield criterion for transversely isotropic materials, which is used for the continuum description for yielding in metal-matrix composites. The proposed surface compares well with the extensive experimental data of Dvorak et al. [1988 “An Experimental Study of Elastic-Plastic Behavior of a Fibrous Boron-Aluminum Composite,” Journal of the Mechanics and Physics of Solids, 36, 655–687] and Nigam et al. [1993 “An Experimental Investigation of Elastic-Plastic Behavior of a Fibrous Boron-Aluminum Composite. I. Matrix-Dominated Mode,” International Journal of Plasticity, 10, 23–48] performed on boron-aluminum metal-matrix composite. Based on the experimentally observed flow and hardening behavior, the elasto-plastic stiffness matrix has been proposed.