The debate over snuck vs sneaked is one of those grammar arguments that feels petty until you're editing a cover letter and suddenly unsure which word to type. Both forms are past tenses of the verb "sneak," and both appear in respected dictionaries. But they don't occupy the same register, and one of them has a history that surprises most people who look it up.
Where each form comes from
English has two classes of verbs. Regular verbs form their past tense by adding -ed: walk becomes walked, clean becomes cleaned. Irregular verbs change their vowel or their whole shape: ring becomes rang, steal becomes stole.
"Sneak" was originally a regular verb. That makes "sneaked" the older and historically standard past tense, and it remained unchallenged in print for centuries.
"Snuck" appeared in American English in the 19th century, formed by analogy with irregular verbs like "stick/stuck" and "strike/struck." Linguists call this process analogical formation. It didn't start as a typo or a mistake. It started as a natural drift in spoken American English, and it stuck.
What the dictionaries actually say
Both forms now appear in Merriam-Webster, which lists "snuck" as a standard variant and notes that it's now more common than "sneaked" in American English. That's a significant endorsement. Merriam-Webster doesn't list nonstandard forms without qualification.
British dictionaries are cooler on "snuck." Collins and Oxford both record it, but as a chiefly North American variant. In British, Australian, and most other varieties of English, "sneaked" remains the dominant form in both speech and writing.
So neither word is wrong. The question is which one is right for your audience.
Formal vs informal contexts
"Sneaked" is the safer choice in formal writing: academic papers, legal documents, journalism following a style guide, and professional correspondence. Most major style guides, including the Chicago Manual of Style, still prefer "sneaked" for careful writing.
"Snuck" fits naturally in informal writing, dialogue, fiction, and everyday American speech. It sounds colloquial because it is. That's not a flaw. A character sneaking out of a party at midnight probably snuck, not sneaked.
Consider the register of what you're writing. A thriller novelist writing American characters loses nothing by using "snuck." A journalist filing for a British publication should probably use "sneaked." This is the kind of call that a punctilious editor will notice.
Quick reference: which to use
- Formal writing, British/Australian English: use "sneaked"
- Informal writing, American English: either works; "snuck" is now more common
- Fiction and dialogue: match the character's voice and setting
The bigger pattern here
The snuck/sneaked split is part of a broader pattern in English where new irregular forms emerge over time and eventually earn dictionary status. "Dove" for "dived" went through the same process in American English. So did "drug" for "dragged" in some regional dialects, though that one hasn't achieved the same mainstream acceptance.
Language changes through use, not through committee. "Snuck" crossed into standard American usage because tens of millions of speakers used it consistently for over a century. Resisting it in casual American writing is, at this point, pedantry. Much like the confusion between payed vs paid, the issue is less about right and wrong and more about knowing which form belongs in which setting.
The one mistake to avoid
Don't mix forms within a single piece of writing. If you use "sneaked" in paragraph two, don't switch to "snuck" in paragraph eight. Inconsistency signals carelessness, and it's the one thing both camps agree on.
Pick the form that suits your register, commit to it throughout, and you won't go wrong with either.