There's a spectrum of behaviors I could recommend here with more information on, say, where the startup is located (because your parents totally aren't insane i

There's a spectrum of behaviors I could recommend here with more information on, say, where the startup is located (because your parents totally aren't insane if the answer is Tokyo) or what stage it is at. For a Valley startup, I think a suit might quite possibly say something about your culture fit that will not be judged in a positive manner, and might suggest anything in the middle of the Venn diagram a) makes you look good and b) could be warn in front of a friend's parents without giving offense in spite of having no prior knowledge of their views on appropriate attire. If you're totally starved for ideas, for guys, khaki pants and a solid shirt, both ironed. I'm even less qualified for giving sartorial advice to ladies than I am to men, so I'll defer to someone else on that. n.b. I fairly often do meetings with startup folks, including potential clients, in either that or my usual jeans + T-shirt with a track jacket on top uniform, and can't remember feeling conspicuously underdressed recently. (Edited to add: Ahh, forgot a conspicuous exception that proves the rule, but I can't disclose it without violating an NDA. Suffice it to say that if the industry a startup is in would make a blind ferret say "Dude, you should dress up for that" then you should probably dress up for that. Still got the engagement but went shopping before I started showing up on site.)