The real ones
"Between Zhou and the butterfly there must be some distinction. This is called the transformation of things." Chapter 2, closing the butterfly dream. Almost always cut off before this sentence, which is the sentence that explains the passage.
"I go in by the natural opening, and strike no blow. The joint gives way of itself." Chapter 3, Cook Ding on carving an ox for nineteen years without dulling a blade. The clearest picture of wu wei in Taoist writing, and note that Cook Ding is working, skilfully and hard.
"You are not a fish. How do you know what fish enjoy?" Chapter 17, Huizi to Zhuangzi on a bridge over the Hao river. Zhuangzi's reply, that Huizi isn't Zhuangzi and so can't know what Zhuangzi knows, is either a brilliant turn or a cheap one depending on your mood. The debate has run for 2,300 years.
"The perfect man has no self, the holy man has no merit, the sage has no fame." Chapter 1. Three ways of describing the same disappearance of the striving ego.
"Everyone knows the use of the useful, but nobody knows the use of the useless." Chapter 4, the summary of the useless-tree stories. The gnarled oak nobody wanted became the only oak that got old.
Misattributed favourites
"Flow with whatever may happen and let your mind be free." Widely captioned as Zhuangzi. It's a loose modern paraphrase in his general direction, not a translation of any specific passage, and the phrasing changes depending on which poster you find it on.
"Happiness is the absence of the striving for happiness." Circulates as Zhuangzi and does compress a real theme in chapter 18. As a quotation it's a modern epigram rather than a line from the text.
"When I let go of what I am, I become what I might be." Attributed to both Laozi and Zhuangzi, and found in neither. It reads like Stephen Mitchell's very free Tao Te Ching rendering, which is probably where the association started. Our Lao Tzu quotes guide tracks the same laundering on the other side.
The pattern is familiar: anything calm and quotable eventually gets a Chinese sage's name attached, because a 2,300-year-old philosopher can't file a complaint.
Why the chapter number matters
Zhuangzi almost always puts his best lines in someone's mouth, and that someone is frequently being mocked. Quote a sentence out of its story and you can end up promoting a position the book is dismantling. Chapter 2 in particular is full of confident assertions that the chapter exists to undercut.
If a Zhuangzi quote arrives without a chapter, treat it as unverified until you find it. Our guide to the Zhuangzi covers which chapters are his in the first place: the Inner Chapters, 1 to 7, with the rest written by later hands.
Reading the source
Burton Watson's translation is the most quotable in English and the source of most lines above. For Taoism at a daily pace, 365 Days of Tao works through the complete Tao Te Ching one verse a morning with sourced commentary, and the free daily email sends the same.
Common questions
What is Zhuangzi's most famous quote?
The butterfly dream from chapter 2, though it's usually quoted without its final line about 'the transformation of things', which is the line that makes sense of it.
Did Zhuangzi say 'flow with whatever may happen'?
Not as a translation of any specific passage. It's a modern paraphrase in his general spirit, and its wording shifts from source to source.
What is the happy fish debate?
Chapter 17. Zhuangzi says the fish are enjoying themselves; Huizi objects that Zhuangzi isn't a fish; Zhuangzi replies that Huizi isn't Zhuangzi. Philosophers have argued about whether that's a fair move ever since.
Which Zhuangzi translation should I quote from?
Burton Watson for general use, Brook Ziporyn when precision matters. Give the chapter number either way.
Are the Outer Chapters really by Zhuangzi?
No. Chapters 8 onward came from later writers working in his tradition. The Inner Chapters, 1 to 7, are the ones generally credited to Zhuang Zhou.