9 Royal Fashion Rules The Princess of Wales Follows (And One She Often Disregards).

9 Royal Fashion Rules The Princess of Wales Follows (And One She Often Disregards).

Dressing like a princess gets a little complicated.

When you’re a duchess, princess, or even the queen, your wardrobe is influenced by royal fashion rules. 

Much has been made of the Windsor family’s rumored dress code—pantyhose and low hems are okay, for example, while bright nail polish and wedge heels are frowned upon—as well as the rare moments when the code is seemingly violated. In truth, the royal fashion rules are closer to guidelines than strict laws. Most are unwritten, and plenty have been broken over the years by different figures.

Princess Diana might be known as a royal rebel in retrospect, but when it came to fashion, she found creative ways to stay within the lines. She "was an absolute expert in knowing what the code is [by 1987],” Caterina Berni, senior interpretations manager of Historic Royal Palaces, told People in 2025. 

Catherine, Princess of Wales, also tends to follow the unspoken rules of regal dressing, but even she will make an exception when the occasion calls for it. As society has evolved, so too have the standards of dress for royal and commoner alike. That doesn’t mean you’ll spot Kate Middleton in a graphic T-shirt and ripped jeans anytime soon, but she might wear denim on a casual outing like walking the dogs. 

Ahead, brush up on the supposed royal fashion rules Middleton and her peers have to follow—and the one she tends to disregard.

1. Wear hats at formal engagements—but only until 6 p.m.

Look at historical photos, and you’ll notice that hats were a bigger feature in everyday fashion than they are today. While it’s no longer general etiquette to wear a topper while out and about, the royal family have kept the tradition alive. “There was a rule that stated ladies could wear hats from the morning at 6 am until 6 pm.,” former royal butler and etiquette expert Grant Harrold told Hello! In 2025. This time limit is set because at 6 p.m., royals would traditionally change into a tiara (if married) or lose their headwear completely.

Queen Elizabeth II was a known lover of hats, wearing them during the majority of her public appearances. In contrast, Middleton and Queen Camilla tend to reserve hats for special engagements. “On general visits, they tend not to wear them, but on more official occasions, they will," Harrold added elsewhere in the Hello! interview.

2. Only wear a tiara if you’re a married royal.

If a royal is single or engaged, you won’t spot them in a glittering tiara at the next diplomatic reception. The bejeweled headpieces are only for married royals, signifying their marital status similar to how a wedding band would, per Vogue Australia. Thus, Meghan Markle and other royal brides have enjoyed their first tiara moments on the day of their ‘I do’s,’ regardless of the length of their engagement and what white-tie events they’ve attended previously.

3. Keep hemlines and necklines modest.

Royal women are expected to keep skirt and dress hems close to the top of the knee, while necklines should avoid revealing cleavage. “It’s all about being modest, elegant and not risking a scandal or causing a media fuss,” etiquette expert and former royal staffer Laura Windsor explained to Reader’s Digest in 2024.

This royal fashion rule is one that several figures have skirted. For example, Middleton has worn dresses with thigh-high slits on multiple occasions, including at a 2016 movie premiere. Markle similarly donned a Reformation dress with a high slit during a 2018 royal tour with Prince Harry, per People.

The same year, the Princess of Wales stepped out in a (re-worn) teal Jenny Packham gown with a V-neck and sheer lace back while attending the Tusk Conservation Awards with Prince William—pushing the envelope, although many royal watchers were quick to point out Elizabeth’s penchant for off-the-shoulder and strapless gowns in her youth.

4. Wear bright colors to stand out in a crowd.

Middleton often wears bright hues, following the example set by the late Queen Elizabeth. It’s not an official fashion rule, per se, but a guideline many royals have since embraced. In her lifetime, the queen made a habit of wearing bright, bold ensembles so that fans who flocked to catch a glimpse of the monarch could more easily spot her in a crowd.

Her daughter-in-law Sophie, Countess of Wessex, explained in the documentary The Queen at 90 (per People), “She needs to stand out for people to be able to say ‘I saw the Queen.’ Don’t forget that when she turns up somewhere, the crowds are two, three, four, 10, 15 deep, and someone wants to be able to say they saw a bit of the Queen’s hat as she went past.”

That’s not to say Middleton never rocks a chic neutral or a muted hue. Her wardrobe is balanced between subtle and standout colors.

Tags: Queen, Prince Charles, Camilla, Prince Louis, Prince William and Kate Middleton, Prince Charles, Prince Harry, Meghan, Lilibet

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