The 2018 Thai League 2 is the 21st season of the Thai League 2, the second-tier professional league for Thailand's association football clubs, since its establishment in 1997, also known as M-150 Championship due to the sponsorship deal with M-150. A total of 15 teams will compete in the league. The season began on 9 February 2018 and is scheduled to conclude on 29 September 2018.

Chainat Hornbill are the defending champions, while Samut Sakhon, Khonkaen and Udon Thani have entered as the promoted teams from the 2017 Thai League 3.

A T2 team could registered five foreign players by at least one player from AFC member countries and at least one player from ASEAN member countries. A team can use four foreign players on the field in each game, including at least one player from the AFC member countries or ASEAN member countries (3+1).

The table lists the positions of teams after each week of matches. In order to preserve chronological evolvements, any postponed matches are not included in the round at which they were originally scheduled, but added to the full round they were played immediately afterwards. For example, if a match is scheduled for matchday 13, but then postponed and played between days 16 and 17, it will be added to the standings for day 16.

Updated to games played on 29 September 2018
Source: Thai League 2
Notes:
^† Teams played previous season in Thai League 3

Source: Thai League 2