Repeatable Read is a database transaction isolation level that ensures if a transaction reads a row of data, it will see the same data if it reads that row again during the same transaction. This prevents other transactions from modifying the data until the current transaction is complete, providing a consistent view of the data. However, while Repeatable Read prevents dirty reads and non-repeatable reads, it does not protect against phantom reads. This means that new rows can be added by other transactions, which may affect the results of queries that rely on the total number of rows.