This article discusses how to dress for a horse show. To figure out how you should dress for a horse show you should find out what type of classes you will be entering and how formal the show is.
For example, how you should dress for a large horse show ran by a national organization might be very different than how you should dress for a horse show ran by a small 4-H club. The best way to find out how formally you should dress for a particular show is to ask someone else who is going and has gone before, or call the organizer of the horse show.
This article on how to dress for a horse show will discuss appropriate wear for schooling (small) horse shows and rated/recognized (large) horse shows.
For English Classes-
(such as, hunter under saddle, hunter over fences, english pleasure, english equitation, dressage, and more)
Standard Apparel: velvet covered helmet, hair pulled back into a hair net (NOT a barrette with hairnet attached), collared "ratcatcher" show shirt in conservative color, show jacket or hunt coat in dark color or grey, tan or beige breeches (white for dressage), belt, and tall black leather riding boots- laced or unlaced are interchangeably acceptable except at the highest levels of competition where unlaced are only worn for dressage.
Minimum Requirements: helmet (preferably black or covered with a black cover), white polo shirt or formal show shirt, a conservative belt, breeches of any conservative color, heeled black boots (tall or short, but short boots should be paired with black half chaps).
For Western Classes:
(such as, western pleasure, western horsemanship, etc)
Standard Show Apparel: More freedom in dress is allowed in western attire but a basic guideline is: Cowboy Hat, a "rail shirt" or slinky with vest, fringed chaps over same-colored pants (coordinated to match hat), and cowboy boots.
Minimum Requirements: Cowboy hat OR helmet, long sleeve collared shirt (preferably with western cut but not required), bootcut jeans, and cowboy boots.
Building a wardrobe for how you should dress at horse shows can quickly become very expensive. To build your show outfits it's best to start either by purchasing used show dress clothes or purchasing the inexpensive "package deals" through some catalogs and then slowly upgrading piece by piece to nicer articles of show clothes.
You should always dress as nice as you are able for a horse show. Small shows aimed at beginners and newcomers to the sport rarely expect each rider to be fully turned out in an expensive show wardrobe, but you should always be as clean and neat as possible and dressed as close to formal as you are able.
It's worth noting that not all shows fall into the "how to dress" categories above. Below are a few additional disciplines in which how you should dress varies from that discussed above:
Western Games/Barrel Racing - These events are based solely on performance, not attire, but most riders wear jeans, a cowboy hat, and a stylish long sleeve western shirt.
Saddleseat - A bowler hat, day coat (longer cut show jacket), jodhpurs, and paddock boots.
Working Cowhorse Events (penning, roping, cutting, etc) - boots, jeans, cowboy hat, and long sleeve collared western shirt.
Western Halter - cowboy hat, boots, slacks, and a western jacket OR rail shirt with collar, cuffs, and hem out.
Sporthorse In Hand or Inspection - Conservative colored polo shirt, khakis or slacks, and comfortable, but nice looking shoes.