A list is mutable — its contents can be changed after creation — while a tuple is immutable, meaning once created, its contents can’t be modified.
Both are ordered collections that can hold a sequence of items, but this mutability difference shapes how and when each is used.
my_list = [1, 2, 3]
my_list.append(4) # works fine
my_list[0] = 99 # works fineWritten with square brackets, lists support adding, removing, and changing elements after creation.
my_tuple = (1, 2, 3)
my_tuple[0] = 99 # raises a TypeErrorWritten with parentheses, tuples cannot be modified once created. This makes them useful for data that shouldn't change — like fixed coordinates — and they're slightly faster and more memory-efficient than lists as a result. Tuples can also be used as dictionary keys, while lists cannot, since dictionary keys must be immutable.
Last reviewed: September 2026