Dress codes for ballroom studios differ from place to place. If you have never taken a ballroom lesson before, it can be difficult to pick the perfect outfit. Whether you are learning a wedding dance or picking up ballroom as a hobby, you can follow these basic principles to make sure you are wearing appropriate clothing. (Note: many studios allow casual dress, in which case the guidelines listed here are not really applicable. Following them may make you feel too dressed up. However, some studios are incredibly strict and won't allow dancers to set foot on the floor unless they are dressed appropriately. I created these guidelines with a stricter studio in mind so dancers are better safe than sorry.)
Think of a ballroom dance studio like a casual theater, office job, or church. You want to wear something slightly dressed up, but obviously casual and athletic enough to move around. Do not wear jeans unless you already know that the studio allows dancers to wear them.
Many studios do not allow jeans both because they are too casual and too hard to dance in. Men should generally wear slacks or khakis with casual or athletic style shirts tucked in (with or without a belt). Avoid cotton t-shirts (they show sweat) and anything with large pictures or logos (small "polo man" and similar is ok).
Women can follow the same principles as men, but skirts and dresses are good too. Just make sure all skirts are knee length or worn over athletic shorts or leggings. Always wear briefs or bootie shorts under skirts, even if they are longer. Any casual or athletic top is acceptable, but try to wear a top with at least wide tank straps and no lace or crochet detail (your partner can get his/her hands tangled). If you are not wearing leggings with your skirt, any nude or black tights or hose including fishnet tights is acceptable. It's also ok to go bare legged, just be sure to put on lotion before you leave the house. Do not wear jewelry (small earrings and rings are ok).
It is also completely acceptable for men and women to wear dancewear such as jazz pants.
For footwear, bring any type of dance shoe you already have (ballet technique shoes, jazz shoes, dance sneakers, character shoes) and wear those for your first lesson. If you don't have any dance shoes, you can probably get away with dancing in dress shoes with slick (fabric or leather) soles or in socks. If you dance in socks, make sure they are black or gray with no logos or designs so they look professional. The most important thing is for you to be able to control your feet as you glide and turn, so socks are often a better choice than rubber soled shoes or wobbly high heels.
If the studio requires dance shoes for all dancers, even for the first lesson, pick up some character shoes from the dance store. These shoes come in men's Oxford and ladies' Mary Jane styles and have hard leather soles that accommodate many styles of dance as well as street wear.
Whatever you decide to wear on your body or your feet, make sure you are comfortable, able to move, and feeling confident.