It's Natural to wonder why followers of the Wesleys were named "Methodists" instead of "Wesley-ists," and there's a good explanation.
In 1729, John and Charles Wesley, along with other students at Oxford, formed a religious society and called it the Holy Club. John led the group and encouraged all members to meet regularly to pray, study Scripture, and have theological discussions. They adopted strict disciplines for their Holy Club because they were convinced that this would lead them toward "inward and outward righteousness." The methodical dedication of the members to their exact disciplines caused other students to mock them and call them "Methodists."