Sport weight yarn is a fine weight of yarn used for knitting and crochet projects. Sport yarn is also sometimes called double knitting (DK). It's the third thinnest yarn after lace and baby weight yarns and just under worsted in thickness. Sport weight yarn is knitted with medium sized knitting needles and crocheted with a medium sized crochet hook. There are many different kinds of sport weight yarns including acrylic, cotton and alpaca.

Sport yarn isn't named after anything having to do with athletics, but rather its name refers to the thickness of knitted or crocheted material it creates. The thickness of garments knitted with sport weight yarn is considered similar to the fabric associated with women's sportswear. Sport weight yarn is a popular yarn for creating lightweight, thinner sweaters.

Lightweight thinner blankets may be knitted or crocheted in sport weight yarn as well. Although sport yarn is heavier than baby weight yarn, it's still popular for knitting and crocheting baby outfits. It's sometimes sold as sport weight baby yarn. Novelty sport yarns often have flecks of texture and color added to a solid background. The yarn is also a good pick for knitting or crocheting thinner dog sweaters and a variety of doll clothes.

Acrylic sport weight yarn is the most economical type and it’s considered practical for knitting children’s wear, as it tends to be tougher than yarns made from natural materials. For softness though, sport weight baby alpaca is the best type of sports yarn. Alpacas are animals in the same family as camels and llamas and alpaca yarn from the first shearing of the animal is the softest. It’s called baby alpaca because of its fine, soft texture.

Organic cotton yarn is available in sport weight. It’s made from cotton grown without pesticides and in many cases without dyes, so organic sports weight cotton yarn is considered an eco-friendly choice. Natural cotton colors can be extremely beautiful shades of brown, tan and white. Good quality organic sport weight yarn can be machine washed in the cold, gentle cycle of a washer and dried on the low heat setting of the dryer. Some shrinking may occur and this may affect the finished knitted or crocheted item, so yarn labels should be carefully checked.