Immutable data structures are types of data structures that cannot be changed after they are created. This means that once you create an immutable object, you cannot modify its contents, such as adding or removing elements. Instead, if you need to make changes, you create a new version of the data structure with the desired modifications. This property helps prevent unintended side effects in programs, making them easier to understand and debug. Common examples of immutable data structures include strings in many programming languages and tuples in Python. They are often used in functional programming, where immutability is a key concept. By using immutable data structures, developers can ensure that data remains consistent and reliable throughout the execution of a program.