No doubt you've seen them in person (if you happen to live in Pennsylvania) or on TV (where they're often mocked). The Amish are a Protestant Christian sect that follow the teachings of 17th century pedagog Jacob Ammann. Their tenets are similar to those of the Mennonites, and their ways are simple. But their clothing... it's also simple, but laden with meaning to them.
The Amish take very seriously the line from scripture of James 1:27 that reads, "and to keep oneself unspotted from the world." They interpret it as not being tainted by those things that are worldly — no extravagances. The same goes for their outfits. The men are meant to wear very basic, simple clothing that does not draw attention.
The men wear what's called broad fall trousers, so called because they have a fall that runs from hip to hip. If you notice, there are no zippers on the broad fall — buttons run across to keep them secured. These came into use around the mid 19th, and have been in fashion in the Amish community since.
The men wear plain button down shirts, as you can see. The shirts are permitted in different colors, ranging from blue, to light blue, to dark blue, sometimes even green. They also come in short- and long-sleeved varieties.
The mutza suit is a suit for special, solemn occasions such as funerals, church, and town meetings. They are distinguished by the absence of any pockets, lapels or collars. So if you need to carry a pencil with you or something... best keep it behind your ear.
If you notice, you'll find that no Amish men wear belts. It is a prohibited accessory — they're just too flashy. Amish men wear suspenders, sometimes two, or, in certain villages, no suspenders at all. But never belts.
Amish women typically make their own dresses, from fabric they buy in their village peddled by Amish folk. The colors range from dark and light blue to pink, and sometimes black if a relative has died. The dress is made with a surplus of cloth, so as not to be revealing in any way, shape, or form. They also can't be high enough to show off the legs.
The women will wear a cape to church, as an expression of their devotion. You will also see them in an apron, which can be white, or a color similar to the dress itself. The apron can be fastened on with buttons or pins, depending on the customs of the particular village.
Amish women are compelled by scripture to either cover their heads, or shear them. Most do the former. This is called the kapp, and is a head cap worn by women starting in their teens. For church, it's white. For home, it's usually black.
Finally, we get to the bottom of this. Men wear plain shoes, black or brown. Work shoes are sturdy, and resilient for tilling the fields. Sometimes the men will wear comfortable sneakers, but they'll usually be black or brown as well, and without logos or things like that.
Women will often go barefoot around the farm and village. But in church, they wear black stockings and black shoes. Or when they need to go out into town, they'll wear the same. But who knows: sometimes they'll even walk into town with nothing on their feet! They're not forced to go without them -- it's just something they do.