The emergence of behavioral finance is based on the knowledge that people do not act rationally as in traditional finance theories. Expectation Theory is the basis of this field. Expectation Theory enables modeling of irrational behaviors by causing changes in decision making methods. The achievement of individuals' financial goals increases the welfare level of the society. Investors who want to achieve their financial goals must also make the right decision. In behavioral finance, there are cognitive and emotional tendencies that affect individuals' investment decisions. These tendencies are called bias. Cognitive and emotional biases help explain investor behavior. Cognitive tendencies most used in the literature; cognitive dissonance, overconfidence, representativeness, availability, anchoring and adjustment, confirmation, conservatism, mental accounting, recency effect, framing effect, hindsight; the most common emotional tendencies; regret aversion, disposition, self-control, social interaction, internet, social media. In this study, the most widely known cognitive and emotional biases in the literature will be discussed conceptually.