Babies can start teething as early as just a few months old, but it might take a while before the actual tooth even appears. In this blog post, I give you tips on how to handle teething, sleep training, and more based on my experience as a sleep consultant for over 10 years. When Does Teething Start? Teething starts around 6 months old, on average. However, some babies start teething before 4 months old while others won't cut their first tooth until after 12 months old. My first son