Bayesian refers to methods in probability and statistics named after the Reverend Thomas Bayes (ca. 1702–1761), in particular methods related to:

• the degree-of-belief interpretation of probability, as opposed to frequency or proportion or propensity interpretations; or
• Bayes' theorem on conditional probability.

These methods include:

• Bayes estimator
• Bayes factor
• Bayesian spam filtering
• Bayesian game
• Bayesian inference
• Bayesian information criterion
• Bayesian linear regression
• Bayesian model comparison
• Bayesian network
• Bayesian probability
• Empirical Bayes method
• Naive Bayes classifier