In this paper we show how to systematically design anti-reflective metasurfaces for the mid-infrared wavelength range. To do so, we have utilized a multilayer arrangement involving a judiciously nano-perforated surface, having air holes, arranged in a hexagonal fashion. By exploiting an effective medium approach, we optimized the dimensions of the surface features in our design. Here, we report a broadband reflectivity 3.5 − 5.5 μm that is below 10% over a broad range of incident angles 00 ≤ θ𝑖 ≤ 700 , irrespective of the incident polarization (TE, TM). Our experimental results are in excellent agreement with full-wave finite element simulations. This systematic approach can be used to design a wide variety of patterned metasurfaces, capable of controlling the phase of the incident optical field.