Yes, sourdough bread typically contains gluten. Gluten is a protein found in wheat and other related grains like barley and rye. Sourdough bread is made from wheat flour, and during the fermentation process, wild yeast and bacteria break down some of the gluten proteins, which can make it easier to digest for some individuals with mild gluten sensitivities. However, it is not entirely gluten-free and is not recommended for those with celiac disease or severe gluten intolerance. People with gluten-related disorders should opt for gluten-free bread alternatives made from non-gluten-containing grains.