Nobody Knows for Sure, But Plausible Theories Include Swords, Servants, and Saddles
For centuries, one of the most puzzling aspects of fashion has been the Button Differential—the curious fact that men's and women's shirts button on opposite sides. If you pause and think about it, can you say for sure whether the buttons on your shirt line up on the left or the right? It may seem like a small detail, but it’s something that has persisted for centuries and continues to influence the way we dress.

The answer is actually pretty simple: Women’s shirts button on the left, while men’s shirts button on the right.

This distinction is not just a trivial oddity. As Megan Garber of The Atlantic pointed out in 2015, “The Button Differential is a relic of an old tradition that we have ported, rather unthinkingly, into the contemporary world.” But why has this design choice stuck around for so long? And where did it come from?

Theories About the Button Switcheroo
Despite how common it is today, no one can say for certain why men’s and women’s clothing buttons are placed differently. Some theories are more plausible than others, but all of them are rooted in historical practices and cultural trends that no longer apply to modern life. One popular explanation ties back to the different ways men’s and women’s clothing used to be worn, particularly during the Renaissance and Victorian eras, when women’s attire was much more elaborate than men’s.

In those times, women—especially wealthy women—wore intricate clothing like corsets, bustles, petticoats, and dresses that were difficult to fasten on their own. As Mental Floss writer Caitlin Schneider explained, “Women—particularly wealthy women—wore elaborate items and often enjoyed the luxury of being dressed by a servant.” These servants, most of whom were right-handed, would have found it easier to button up their employers’ dresses if the buttons were placed on the opposite side than on men’s clothing. As men’s attire was simpler and easier to manage alone, they had shirts with buttons on the right.

Over time, as mass-produced clothing became widespread, this design choice stuck. And even though women today can certainly dress themselves without the help of a servant, the design hasn't changed.

But Why the Left Side for Women?
Some have theorized that this buttoning pattern had to do with how women once rode horses—specifically, how women rode sidesaddle. Riding sidesaddle meant that the right side of a woman’s body faced forward, and the buttoning on the left would have helped protect her from the wind or the elements. This theory is often brought up in discussions of historical fashion, but it’s worth noting that there's no definitive proof that this was the original intention for the design.

Other theories claim that women’s shirts were designed for mothers who were likely to hold their babies in their left arm, leaving their right hand free. With this in mind, buttons on the right side would have been more convenient for breastfeeding. The suggestion is that, in this case, the button placement served a practical function for women with children, making it easier for them to manage their clothing while attending to their babies.

Some even claim that the button difference was intentionally designed as a way to emphasize gender differences. The argument goes that the opposite sides symbolized the division between men and women, with men’s clothing representing power and masculinity and women’s clothing reflecting submission or delicacy.

What About Men’s Buttoning?
On the flip side, there are theories about why men’s shirts button on the right. One popular explanation is that this design choice is a relic of military traditions. Historically, men’s clothing was influenced by the need to wear armor and be ready for battle. For instance, armor was designed with overlapping plates that fastened from left to right, as this direction provided better protection. The left side was the side men shielded with their arm during battle, and the right side was left open for combat. It’s believed that the buttoning style in men’s clothing was an extension of this tradition, and the right-to-left fastening helped protect the wearer from blows and allowed for easier access to weapons.

Moreover, because most soldiers carried their swords on their left side to be drawn with their right hand, a shirt that buttoned on the right allowed for better movement and less interference with the sword's handle. According to A Gentleman’s Wardrobe author Paul Keers, "A gentleman’s sword was always worn on the left side, so that it could be drawn with the right hand. If a jacket buttoned right over left, the handle of the sword would be likely to catch in the jacket opening when drawn." Thus, military influence shaped the buttoning style for men’s clothing.

The Napoleon Theory
Some of the theories surrounding the Button Differential are a bit more outlandish. For instance, one suggests that the discrepancy between men’s and women’s button placements is thanks to Napoleon Bonaparte. It is said that Napoleon often posed for portraits with his hand inside his waistcoat, and women would mock him by copying this pose. According to the story, Napoleon ordered that women’s shirts be buttoned on the opposite side of men’s to prevent women from imitating him in this way. Though this story is fun, it’s widely regarded as more of a myth than a historical fact.

Why Do We Still Follow This Tradition?
Despite the many plausible theories, the real question remains: Why has this tradition persisted into modern times? Why haven't we swapped the button placements now that women are fully capable of dressing themselves? As Live Science writer Benjamin Radford put it, "There’s no real reason the buttons couldn’t be switched. It’s just that nobody has bothered to change a tradition that few people notice or complain about in the first place."

Today, the Button Differential is just another curious detail that many people don't give much thought to. However, it serves as a reminder of the deep-rooted traditions that continue to shape the world of fashion, often in ways we don’t even realize.