In React, there are two types of components: functional and class components. Here are the differences between them:

Functional Components:

1. Definition:
   Functional components are JavaScript functions that take in props as input and return a React element.

2. State:
   Functional components do not have state. This means that they cannot store data or update it in response to user events.

3. Lifecycle methods:
   Functional components do not have lifecycle methods. This means that they cannot perform actions when the component mounts, updates, or unmounts.

4. Performance:
   Functional components are generally faster and less memory-intensive than class components, since they do not have a lot of the overhead associated with class components.

Class Components:

1. Definition:
   Class components are ES6 classes that extend the React.Component class. They define a render() method that returns a React element.

2. State:
   Class components have state, which allows them to store and update data in response to user events.

3. Lifecycle methods:
   Class components have lifecycle methods, which allow them to perform actions when the component mounts, updates, or unmounts.

4. Performance:
   Class components are generally slower and more memory-intensive than functional components, since they have a lot of the overhead associated with class inheritance and the React.Component class.