Marketing qualified leads (MQL) is one of the stages a lead goes through prior to becoming a customer. A marketing qualified lead is someone who has expressed interest in your product or service, indicated a challenge, pain or opportunity they are facing but they have not yet indicated a desire to enter into a sales process. For example, they have downloaded a white paper or eBook, but they have not looked at your “Contact Us” or “Request a Demo” pages. Once a MQL takes these steps, they become a Sales Qualified Lead (SQL).