The 2018–19 Premier League Tournament Tier B was the second division of the 31st season of first-class cricket in Sri Lanka's Premier Trophy.

The tournament was contested by nine teams, starting on 31 January 2019 and concluding on 23 May 2019.

[1] Negombo Cricket Club won the tournament in the previous season and were promoted to Tier A.

[2] They were replaced in Tier B by Bloomfield Cricket and Athletic Club after their relegation from Tier A.

[3] Lankan Cricket Club won the tournament and secured promotion to Tier A, after finishing top of the points table ahead of Sri Lanka Navy Sports Club.