The 4m Advanced Technology Solar Telescope (ATST) is the next generation ground based solar telescope. In this paper we provide an overview of the ATST post-focus instrumentation. The majority of ATST instrumentation is located in an instrument Coude lab facility, where a rotating platform provides image de-rotation. A high order adaptive optics system delivers a corrected beam to the Coude lab facility. Alternatively, instruments can be mounted at the Nasmyth focus. For example, instruments for observing the faint corona preferably will be mounted at Nasmyth where maximum throughput is achieved. In addition, the Nasmyth focus has minimum telescope polarization and minimum stray light. We give an overview of the initial set of first generation instruments: the Visible-Light Broadband Imager (VLBI), the Visible Spectro-Polarimeter (ViSP), the Near-IR Spectro-Polarimeter (NIRSP), which includes a coronal module, and the Visible Tunable Filter. We also discuss the unique and efficient approach to the ATST instrumentation, which builds on the use of common components such as detector systems, polarimetry packages and various opto-mechanical components. For example, the science requirement for polarimetric sensitivity (10-5 relative to intensity) and accuracy (5'10-4 relative to intensity) place strong constraints on the polarization analysis and calibration units. Consequently, these systems are provided at the facility level, rather than making it part of the requirement for each instrument.