For an enterprise company always wear a suit. For a C level interview wear a suit, regardless of environment in my opinion. If a startup comments about you bein

For an enterprise company always wear a suit. For a C level interview wear a suit, regardless of environment in my opinion. If a startup comments about you being overdressed just have some fun with it. For mid-sized firms it can go either way, suit or just business attire with or without tie. For small firms, dress appropriately to the company, as someone else said, dress at least 1 level up from what they are wearing daily. Also, you can always ask the phone screen person or HR rep. Say hey, what is the daily dress code like? Or be more direct and say hey I like to make sure I am respectful of your environment and would normally wear slacks and a button down shirt, would that be acceptable for an interview with your team? Frankly I have had only a few people ever ask me and they stood out in my mind positively as conscientious. Financial services/banks etc, always wear a suit. A few other industries are like this too from my experience.