A linked list is a fundamental data structure in Python that consists of a sequence of nodes, where each node contains data and a pointer to the next node in the sequence. Unlike traditional arrays, linked lists allow for efficient insertion and deletion of elements, as they do not require contiguous memory allocation. There are two main types of linked lists: singly linked lists, where each node points to the next node, and doubly linked lists, where nodes have pointers to both the next and previous nodes. Understanding linked lists is essential for effective data management and manipulation in programming.