Grandad Shirt Club is a clothing company dedicated to providing high-quality, 100% cotton shirts designed with both style and practicality in mind. We pride ourselves on sourcing fair-trade and eco-friendly products whenever possible, ensuring our business operations align with our commitment to ethical and sustainable practices. Our product range champions brands for men that are sourced predominantly from UK suppliers, blending a unique mix of ethnic style and boho vibes. We aim to source practical outdoor gear. At Grandad Shirt Club, we also strive to offer fast delivery whenever possible, ensuring our customers receive their top-notch products promptly. Further solidifying our confident promise to customer satisfaction, all purchases come with a customer guarantee. Our mission is to provide an exceptional shopping experience that aligns with our values and quality standards while infusing a unique style into the wardrobe of every man.

Straight from Wikipedia 

'A Grandfather shirt or Granddad shirt or "50s T-Shirt" is a long-sleeved or short-sleeved flannel or brushed cotton band collared shirt worn throughout Ireland. Traditional shirts are white with coloured vertical stripes. Longer shirts are used as nightshirts or pajamas. The nightshirt version can include a matching nightcap.

The style of shirt (called a union shirt) was also worn by working-class men in the United Kingdom during the industrial era. At this period, the lack of a turndown or collar "cape" was filled by the use of a detachable collar. The 2010s decade has also seen the garment feature as a mainstream fashion item for men.[1][2]

The grandfather shirt is also made of Irish linen. The linen version is colloquially known as a 'Sunday shirt'. Sunday shirts are often paired with black trousers or Irish tweed pants and worn to mass, christenings, funerals, and weddings.

In popular culture, a variety of traditional Irish clothing was featured on the BBC series, Ballykissangel and the Irish folk band, The Clancy Brothers were often photographed wearing traditional Irish clothes.

An identical collarless shirt or tunic, known as a kurta, is traditionally worn in the Islamic world and South Asia. This usually has three or four buttons, and is often decorated with intricate embroidery.'