In JavaScript, objects are collections of key-value pairs. You can access these values using either dot notation or bracket notation. Dot notation is more straightforward and easier to read. It's used when you know the property name. For example, if you have an object 'person' with a property 'name', you can access it like this: person.name. Bracket notation, on the other hand, is more flexible. It allows you to access properties using variables or property names that may not be valid identifiers. For instance, if a property name has spaces or special characters, or it's a number, you can access it like this: person['property name'].