John Slater, MLA for Boundary-Similkameen, was first elected in 2009 and told the party last year he would not be seeking re-election.
Slater recently changed his mind and wanted to run again, but the Liberals would not allow him to be re-nominated to represent the party.
A B.C. Liberal spokeswoman said Slater's candidacy had not been approved because of personal issues that would impact his ability to represent the party. The issues were not identified.
Slater responded to the decision by saying on Twitter that he would continue to sit in the legislature, but as an independent.
Slater becomes the current legislature's fourth independent, joining maverick MLAs Vicki Huntington, Bob Simpson and John van Dongen.
The move drops the B.C. Liberals to 45 members. B.C. New Democrats have 36.