Pretty much all the same.

They are all very similar, basically the same. "Business hours" - shows the opening and closing time for any type of business. "Office hours" - shows when an office will be open and closed (some businesses have business hours and contain an office that has different hours). "Opening hours" - means the same as "Business Hours" in British English, but we don't really use that term in American English. We might use "Hours of Operation".