There’s a tiny detail on most shirts that you may never have questioned: men’s and women’s shirts usually have buttons on opposite sides. Men’s shirts typically button on the right, while women’s garments traditionally button on the left. But this simple difference may have roots in centuries-old fashion, social customs, and practicality.

Buttons became popular in Europe during the Middle Ages, when they were expensive and often made from precious materials such as gold, silver, pearls, ivory, and gemstones. For wealthy families, clothing could be a way to display status and wealth. One widely shared explanation for women’s buttons is connected to wealthy women having servants help them dress. Since most people were right-handed, placing the buttons on the woman’s left side may have made them easier for a servant facing her to fasten.

Men’s button placement is often linked to practicality and military traditions. Right-side buttons may have made garments easier for right-handed men to open or adjust, particularly when carrying weapons. Military uniforms also had a powerful influence on civilian fashion, and details from military clothing often became part of everyday menswear.

Over time, the original reasons became less important, but the tradition remained. Today, there is little practical need for men’s and women’s shirts to button on different sides, yet manufacturers continue the convention because people recognize and expect it. So, the next time you button a shirt, remember that this tiny fashion detail may carry centuries of history—reflecting class, servants, military life, and changing social customs.