Hello,

I already work for an organization in a specific capacity. However, I recently saw and responded to an ad with the same job title that I have now. The ad did not state the name of the organization only the city and state. It was not at all clear if this was my organizations' ad. I applied becaue could use the extra money. If this is my employers' ad that I responded to could I be let go for responding? Or is it none of their business if I search for more work?

Thank you,

Concerned Applicant.

It is none their business until they actually receive your notice of leaving.

My comments are based on an assumption that it was an ad put out by your company.
They shouldn't hold it against you but depending on the personalities involved-they might. I know of an employee who was fired for a slightly similar episode but his name had appeared in a competing company's proposal for work with a government agency, so it was quite different than your case.
If your work is satisfactory I doubt that you will be fired for the response to an ad. But they may have doubts about your loyalty to the company and it could affect your position if there were layoffs or cutbacks, and maybe if you had promotional opportunity it could go against you.
You might consider talking to your supervisor about it and attempt to explain that you are happy in your position but you had hoped to find something part time to help pay the bills but you had no way to tell but if it was a competitor you wouldn't have taken the position.
Only you know if you can pull that off based on your relationship with management and if there is some way to take this from a negative to at least slightly positive. Or maybe turn it into something that everyone gets a chuckle out of and forgets about it.
Many job ads get tons of responses submitted nowadays. Any chance that it won't be noticed? Or do you know anybody in HR who could pull it out of the pile for you? Or was it an electronic submittal?
Good luck. This is an unfortunate incident that probably happens frequently because many ads do not divulge the name of the recruiting company.

... could I be let go for responding?

Most employment is "at will". An employer can fire you for any reason, or for no reason at all. If this pertains to you, the answer would be "yes".

'Extra money' in addition to the job you have, or because you would quit this one to earn more?