The purpose of this research is to study the relationship between goodwill arising from merger and performance of the listed companies in the Stock Exchange of Thailand during the period of 2012 – 2015. There were 583 firm-year observations collected from 55 listed firms was analyzed using multiple linear regression methodology to find the relationship between the balance forward goodwill, the goodwill that is generated during the year, and that which has decreased, and the performance which is measured by total revenue.