The 2017–18 Nemzeti Bajnokság III is Hungary's third-level football competition. On 20 June 2017, the play-offs finished and the full tables were formed. On 26 June 2017, it was announced that the Hungarian Football Federation did not accept the of Szigetszentmiklósi TK. On 12 July 2017, the Hungarian Football Federation issued the three groups of the 2017–18 season. On 28 March 2018, the STC Salgótarján announced its withdrawal from the 2017–18 Nemzeti Bajnokság III season. The results for STC Salgótarján were deleted for the entire season due to their withdrawal.