Self-organizing networks able to adapt to changes in the environment have already been a longstanding research topic. Given the limited number of license-free Industrial, Scientific, and Medical (ISM) radio bands, wireless technologies end up competing with one another for the wireless spectrum. As such, the proper employment of Medium Access Control (MAC) protocols is essential to guarantee efficient and reliable wireless communication. At the data link level, there has been extensive research towards programmable and more future-proof MAC protocols (e.g., Software-Defined Radios (SDRs), which enable to reconfigure the entire protocol and hence access/control finegrained radio functionalities). However, actual deployments are so far limited because of performance issues and cost. With the increasing popularity of Software-Defined Networking (SDN), also in the wireless domain, and the increasing performance of SDRs, we are evolving into a fully programmable data link layer. In this survey, we deliver: a landscape of the state-of-theart on programmable MAC protocols; a coherent terminology that represents scope and level of programmability supported; an in-depth study of their advantages and disadvantages; and a discussion about future research challenges on MAC programmability. Many surveys have investigated the use of specific MAC protocols for a wide range of optimization criteria and application demands. This survey is the first that investigates the scope and the level of programmability that MAC protocols support. TABLE I RELATED SURVEYS ARTICLES ON WIRELESS MAC PROTOCOLS AND THEIR MAIN TARGETS. Authors Year Main Target Focus Technology H. Peyravi [18] 1999 Classify MAC protocols based on five classes: fixed assignments, Mode-of-operation Satellite Networks demand assignment, random access, hybrid of random access Performance and reservation, and adaptive protocols. Reconfigurability A. C. V. Gummalla 2000 Classify MAC protocols based on architecture design, Mode-of-operation Wireless Networks and J. O. Limb [19] mode-of-operation, performance, and application domain. Architecture S. Kumar, V. S. 2006 Classify MAC protocols based on their brief description, Mode-of-operation Ad Hoc Networks Raghavan, and J. Deng [20] mode-of-operation, and underlying features. Underlying Features I. Demirkol, C. Ersoy, 2006 Describe MAC protocols emphasizing energy consumption, Mode-of-operation WSNs and F. Alagoz [21] strengths and weaknesses. Energy efficiency T. V. Krishna 2009 Compare MAC protocols for centralized and decentralized Architecture CRNs and A. Das [22] Opportunistic Spectrum Access (OSA) networks. Reconfigurability C. Cormio and 2009 Compare MAC protocols according to its features and the Mode-of-operation CRNs K. R. Chowdhury [23] different modes-of-operation. Underlying features M. J. Booysen, S. Zeadally, 2011 Survey the different MAC protocols focusing on the benefits and Mode-of-operation Vehicular Ad Hoc and G. J. van Rooyen [24] limitations of their mode-of-operation on future deployments. Performance...