Celiac disease (CD) is a permanent auto-immune enteropathy, triggered in genetically predisposed individuals by the ingestion of dietary gluten. Gluten is the alcohol-soluble protein component of the cereals wheat, rye and barley. CD is a multifactorial condition, originating from the interplay of genetic and environmental factors. The necessary environmental trigger is gluten, while the genetic predisposition has been identified in the major histocompatibility complex region on chromosome 6p21, with over 90% of CD patients expressing HLA DQ2 and the remaining celiac patients express DQ8. The fact that only about 4% of DQ2/8-positive individuals exposed to gluten develop CD, has led to the recognition that other genetic and environmental factors are also necessary. In the last few years, several epidemiological studies have suggested that the timing of the introduction of gluten, as well as the pattern of breastfeeding, may play an important role in the subsequent development of CD. Here, we present and review the most recent evidences regarding the effect of timing of gluten introduction during weaning, the amount of gluten introduced and simultaneous breastfeeding, on the development of CD.