帕金森琐碎定理（英语：Parkinson's Law of Triviality），又译为帕金森氏凡俗法则，或称芝麻蒜皮定律、芝麻绿豆定律，由英国历史学者与政治学者西里尔·诺斯古德·帕金森（Cyril Northcote Parkinson）于1957年所提出，用来说明大型组织会花费大量时间在讨论无关紧要的琐事，但是真正重大的决议反而可以轻松过关这种现象。这是由于人对大议题较难有全面性的理解，故怕贸然提出异议，可能会失言；相反地，对于一些简单琐碎的小事，有相当的认识，因此意见特别多，造成组织在各事项上讨论所花费之时间，通常与事项本身的重要程度呈现反比。

Parkinson's law of triviality is C. Northcote Parkinson's 1957 argument that members of an organisation give disproportionate weight to trivial issues. He observed that a committee whose job was to approve the plans for a nuclear power plant spent the majority of its time on discussions about relatively minor but easy-to-grasp issues, such as what materials to use for the staff bike-shed, while neglecting the proposed design of the plant itself, which is far more important but also a far more difficult and complex task.