What type of stitch is commonly used for sewing stretchy fabrics?

The zigzag stitch is commonly used for sewing stretchy fabrics. Its distinctive side-to-side pattern allows the stitch to flex and extend with the fabric when it is stretched, then return to its original position without breaking. A straight stitch, by contrast, forms a rigid line that will snap under tension when the fabric stretches.

The zigzag stitch is versatile on stretch fabrics: it can be used for seaming, hemming, and applique. Adjusting the stitch width and length allows the sewer to control how much stretch the seam can accommodate. It is available on virtually all domestic sewing machines, making it the most accessible stitch for working with knits and other elastic materials.

An overlock stitch (produced by a serger/overlocker) is excellent for finishing edges and sewing stretch seams, but it is a specialised stitch that requires a separate machine, not the standard answer for a basic sewing question. A straight stitch has no lateral give and will break when stretched. A basting stitch is a long, temporary stitch used for holding fabric in place before permanent sewing and is not suitable for any finished seam.