While there is no "official" written dress code published on your ticket, the White House strongly encourages "Smart Casual" or "Business Casual" attire out of respect for the historic nature of the building. Think of it like dressing for a nice lunch or a house of worship. Most visitors wear slacks or nice jeans (no rips) paired with a collared shirt, blouse, or sweater. Comfortable walking shoes are the most important part of your outfit, as the tour involves a significant amount of standing and walking through the East Wing and Residence. You should avoid overly revealing clothing, gym wear (like "short shorts" or tank tops), or clothing with offensive language. It is also important to dress for the weather; you will likely spend time waiting outdoors in a security line before entering. Finally, keep in mind that you cannot bring bags or purses of any size, so choose an outfit with secure pockets if you need to carry your phone and ID.