In general, wear what you should have worn with trousers in the same situation, only everything should, with a tartan kilt, be monochrome.

On your head

A cap, a sun hat or nothing.
Unless you are Scottish and the situation or event calls for it, a bonnet or other Scottish headwear will most likely make a caricature out of you.

On your upper body

A t-shirt, polo shirt, oxford shirt, in fact, any shirt you should otherwise have worn with trousers or shorts.

Shirt tucked-in or untucked?

Tucked-in is the general answer, and on which purists insist. And with Oxford shirts, I agree. However, men today are increasingly wearing t-shirts and polo shirts untucked when wearing jeans and shorts; why should it be different when wearing a kilt for casual wear? In general, I prefer tucked-in shirts.



Depending on the temperature, a sweater over your shirt is what to wear and always untucked, of course. A nice hoodie is also a possibility.

As outer wear on cold days, a short wind breaker (bomber jacket type) or anorak will be perfect and look nice with your kilt.

Never wear a coat, covering your kilt and, like already mentioned, never one of your normal jackets which should be too long and look totally wrong.

On your legs and feet

After Brexit, inexpensive items like kilt socks have become absurdly expensive for EU citizens. The reason is that the declaration fee might exceed the price of the socks. You can either buy more at a time to share the fee or look for alternatives.

Must I wear kilt socks when temperatures are high?

According to the purists, and the 'Kilt Police', YES of course, but they will probably accept them scrunched down.
In that case, you can wear suitable, cheaper knee-high socks. When scrunched down, nobody can tell the difference, and the knee-highs shall, due to less material, feel more comfortable.

Also, on a hot day I think that short socks or “invisible” socks or no socks are making a lot more sense than thick woollen kilt hose - provided the kilt is worn as casual wear and not to a wedding where a dress code must be followed.

Could I wear knee-high socks, which are thinner than kilt hose?

No, not if rules are to be followed. But if you think your calves must be covered and temperatures are high, and you are probably the only man wearing a kilt, which is almost always the case, I don't see why you should not wear thinner knee-highs.

But optically, then thin, non-transparent over-knee socks, which can be folded down under your knees like kilt hose, are the better choice. Then you must either visit a women's store or order online.

Can I wear tights or leggings on a cold day?

The YouGov research, mentioned earlier, indicated that some kilt wearers wear tights or leggings under their kilts. On kilt forums, where it has been discussed, some are OK with it; others (most) are against. But after all, you can see men wearing them under shorts, so why not? They should be non-transparent, of course. And you might consider wearing kilt hose over your tights.

When HRM King George IV in 1842 visited Scotland (it was the first visit of a British monarch to Scotland in 183 years) he, at the grand ball, was wearing pink tights, in a newspaper described as "buff coloured trowsers like flesh to imitate his Royal knees under a rather shortish (meaning too short) kilt".

Let me say it this way: When introducing your kilt-wearing to your surroundings, refrain from items that are (too closely) related to the female wardrobe. Wait a bit with tights and leggings, at least as a fashion statement.
I seldom wear tights with my kilts as a pure fashion statement, but yes, it happens.

Footwear

Wear shoes fitting the purpose. For casual occasions, sneakers are often a suitable choice. Heavy-duty shoes and walking boots are also popular. Or loafers and dress shoes. Simply, wear shoes you would have worn to similar occasions, in trousers.

If I let go of the sporran?

A shoulder bag is the obvious choice. Men already wear them, so no big deal about that and suitable ones should be easy to find. For example, Eastpack makes some nice shoulder bags. You can have them about the size of a sporran, or larger to accommodate an iPad Mini, a regular iPad, or a laptop. And in many colours. They are all unisex.

Often, you’ll have pockets enough in windbreakers, etc.



By the way, the kilt itself, being unusual and thus an eye-catcher to some extent, might, compared to neutral jeans and shorts, provide some added security against pickpockets, who want to operate as unnoticed as possible.

Colour coordinate

Think colour scheme when wearing a kilt. Colours of other clothing items should always be in harmony with one of the colours in your tartan or match them.

Under your kilt

What you wear – or don’t wear - under your kilt (or trousers) is a matter of personal preference. But the idea of wearing the kilt “like a true Scotsman” regularly might appeal to many. Probably every kilt wearer has tried 'going without' at least once, this being part of the game, so to speak.
However, before you ditch your underpants, keep in mind: Wool kilts must be dry cleaned, and even if some PV kilts are machine washable, they may still require a lot of ironing.

Considering that almost half of all kilt wearers (according to the earlier-mentioned YouGov research) do not wear regular underwear under their kilt, there should exist a significant market potential for a solution that addresses the hygiene issue while still ‘letting them feel the breeze’.

The solution is called a kilt liner. But even if it makes a lot of sense, obviously, nobody is making or selling them anymore.
The company, which has recently stopped marketing them, had a very old-fashioned website, which was a good reason why it couldn't continue.
Another reason might be that kilt wearers have found other solutions regarding the hygiene question. Or they wear their kilt so seldom that the hygiene factor is not an issue.

A kilt liner is, or was, simply a thin skirt or a half slip. Instead, a so-called skater skirt will do the job. And this might be what many kilt wearers have realised and now practice.



Such a skirt is, contrary to what the ‘authorised’ kilt liner was, wide, really wide, and accordingly much more like a kilt, in fact. The elastic waist and jersey fabric are what you are familiar with from your underwear or sports clothes. So, nothing feminine per se about that. When worn under a kilt, a skater skirt is just open, roomy underwear, which shall protect your precious kilt efficiently against you.

The skirt shown under the kilt above is grey, but unless the kilt is grey, a black skirt is preferred, because it better 'disappears' into the shadow under your kilt.

But how about comfort, you may ask? Try it out. I guess you'll find the “semi-commando” solution coming very close to the ‘real thing’.
However, if you think tradition must be followed, forget this advice and do what you must.
To mention: On windy days or when you have to sit a lot, there certainly are better, more straightforward solutions than going full- or semi-commando. And even then, the kilt is a most comfortable garment.