A party at a bar is usually a fun occasion, so you should enjoy yourself. However, you still need to make sure you are dressed appropriately. As long as the venue is not a dive-bar, business casual clothing is the best option for what to wear to a party at a bar.
Unless the party is for a specific occasion that requires non-traditional clothing, the advice provided for what to wear to a bar is appropriate for a party at a bar. This includes trendier business casual clothes - dark pants, button-down shirt, matching shoes/socks/belts and for the right type of bar jeans.
Sometimes a party at a bar can require nicer clothing than normal
Remember that you'll be standing, so wear comfortable shoes
Review the advice section about what to wear to a bar
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