Leave Alone vs. Let Alone (Grammar Rules)
Learn the differences of leave alone and let alone on with Grammar Rules from the Writer’s Digest editors, including a few examples of correct usages.
Q: Can you differentiate let and leave (as in, "Let me alone" and "Leave me alone")? I get confused as to when each should be used. –Jan I.
A: There is a pretty simple difference between let and leave when used in this context, and it's quite easy to explain.
“Leave alone” means to leave a person all by himself (in solitude). Please leave me alone, I don't want company. Alvin needs to study, so let's leave him alone in his room.
“Let alone,” on the other hand, means to stop bothering the person. Stop poking my leg and let me alone, Simon; I'm trying to watch TV. Theodore wanted his singing coach to let him alone instead of critiquing his singing. (And yes, I am going with a Chipmunks theme here.)
While the definitions above are the traditional uses of both words, it is becoming more common (and more acceptable) to use "leave me alone" in both contexts. But if you want to be a grammar purist, keep them separate.
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No matter what type of writing you do, mastering the fundamentals of grammar and mechanics is an important first step to having a successful writing career.

Jane Friedman is a full-time entrepreneur (since 2014) and has 20 years of experience in the publishing industry. She is the co-founder of The Hot Sheet, the essential publishing industry newsletter for authors, and is the former publisher of Writer’s Digest. In addition to being a columnist with Publishers Weekly and a professor with The Great Courses, Jane maintains an award-winning blog for writers at JaneFriedman.com. Jane’s newest book is The Business of Being a Writer (University of Chicago Press, 2018).