Do you need a visa visiting Spain on a Gambian passport living in the UK married to a british citizen?

Yes, as a Gambian passport holder, you will need a visa to visit Spain, even if you are living in the UK and married to a British citizen. You should apply for a Schengen visa, which allows you to travel to Spain and other Schengen Area countries. It's advisable to check the specific requirements and application process at the Spanish consulate or embassy. Keep in mind that your marital status may assist in demonstrating ties to the UK, but it does not exempt you from needing a visa.