Expect to come across this popular scenario based SQL JOINS interview question. Indexes can significantly improve the performance of JOIN operations by allowing the database to locate the rows to be joined. Without indexes, the database would have to scan through all rows of both tables to find the matching rows, which can be slow for large tables. By creating indexes on the columns used in the JOIN condition, the database can quickly locate the matching rows and perform the JOIN more efficiently. However, it is important to balance the benefits of indexes with the overhead of maintaining them, as they can also impact the performance of INSERT, UPDATE, and DELETE operations.