Legal Templates » What is Promissory Note Articles tagged: What is Promissory Note Subscribe Submit an article What is Promissory Note? A promissory note also referred to as an IOU or loan agreement is a written promise to pay someone within a specific time period. Trinity Hanson | 06/09/2021 Like what you just read? Subscribe to our newsletter and be the first to hear of the latest Zegal happenings, tips and insights! Please leave this field empty.