Having overdraft protection can help you avoid checks bouncing if you accidentally write one for more than your current balance. Often, just having overdraft protection won't affect your credit score unless you use it, can't pay it back and the bank turns it over to collections (in this instance your credit score can go down). However, some overdraft protections are structured as lines of credit, which could affect your credit score.

Line of Credit Effects

If your bank treats your overdraft protection as a line of credit, that can affect your credit score when it's reported to the credit bureaus. If you never use it, that extra line of credit decreases your credit utilization ratio -- a measure of how much of your available credit you're using at any given time -- which increases your credit score.