《威利在哪里？》（英文：Where's Wally?），也译《威力在哪里？》、《大家一起找沃里？》、《聪明的沃里？》，是一套由英国插画家Martin Handford创作的儿童书籍。这个书的目标就是在一张人山人海的图片中找出一个特定的人物——威利。威利穿着红白条纹的衬衫并戴着一个绒球帽，手上拿着木制的手杖，还戴着一副眼镜。他总是会弄丢东西，如书本、野营设备甚至是他的鞋子，而读者也要帮他在图中找出这些东西来。

这套书是一系列复杂的全页绘图册，图中有上百个人在做各种不同的事情。读者的目标就是从这些人中找出威利，但威利总是躲在很隐蔽的地方。例如，在“威利在哪里3：梦幻之旅”中有一张特别困难的任务，这张图里有上百个不同的威利，而读者只能通过他丢失的鞋子来找出哪一个才是真的威利。

Where's Wally? (known in the United States and Canada as Where's Waldo?) is a series of children's books created by the English illustrator Martin Handford. The books consist of a series of detailed double-page spread illustrations depicting dozens or more people doing a variety of amusing things at a given location. Readers are challenged to find a character named Wally hidden in the group. Wally's distinctive red-and-white-striped shirt, bobble hat, and glasses make him slightly easier to recognise, but many illustrations contain red herrings involving deceptive use of red-and-white striped objects. Later entries in the long-running book series added other targets for readers to find in each illustration. The books have also inspired a TV show, comic strip and a series of video games.