* Bayesian* refers to methods in probability and statistics named after Thomas Bayes (c. 1702–61), in particular methods related to statistical inference:

- Bayesian probability or degree-of-belief interpretation of probability, as opposed to frequency or proportion or propensity interpretations
- Bayes' theorem on conditional probability
- Bayesian inference

These methods include:

- Bayes estimator
- Bayes factor
- Bayesian average
- Bayesian spam filtering
- Bayesian game
- Bayesian inference
- Bayesian information criterion
- Bayesian multivariate linear regression
- Bayesian linear regression, a special case

- Bayesian network
- Empirical Bayes method
- Naive Bayes classifier
- Bayesian additive regression kernels
- Bayesian econometrics
- Bayesian experimental design
- Bayesian inference in phylogeny
- Bayesian search theory
- Bayesian vector autoregression

Bayesian also refers to the application of this probability theory to the functioning of the brain

- Bayesian brain