This article examines Ibn Taymiyyah’s views on “Sunnah” and “Bid’ah,” and analyzes his definitions, classifications, and the criticisms leveled against his viewpoints. The importance of this issue stems from the influence of Ibn Taymiyyah’s perspective in considering some religious practices of Muslims as innovations by Wahhabis. Ibn Taymiyyah defines Sunnah as a belief or action that the Prophet (pbuh) and his companions continuously adhered to. He divides Sunnah into “Sunnah in action” and “Sunnah in abstention” (Tarkiyyah Sunnah), emphasizing that the Prophet’s (pbuh) abstentions also have a legal ruling. In defining Bid’ah, he applies it to any new action without a prior religious basis and any practice that lacks a legal justification. He also divides Bid’ah into “Bid’ah in words and beliefs” and “Bid’ah in actions and worship,” considering any kind of innovation in religion as Bid’ah. The findings of this research reveal some flaws in Ibn Taymiyyah’s view, such as the unjustifiable expansion of the scope of Bid’ah, the failure to accurately outline the pillars of Bid’ah, and opposition to the famous opinion of Sunni Muslims regarding the division of Bid’ah into good and bad.