This paper aims to analyze a time-varying relationship between corporate governance and expected stock returns in Thailand. The time variation of corporate governance premium is estimated by macroeconomic determinants using a two-state Markov switching model. The results indicate the presence of asymmetries in the variations of corporate governance premium over the Thai economic cycles. Investors can take advantage of the time-varying characteristics with the adaptation of switching investment strategy. Incorporation of style switching strategy with value premium in recessions and momentum premium in expansions improves expected returns of corporate governance-sorted portfolios.