Past Tense of “sneak”
The past tense of sneak is sneaked; the past participle is sneaked.
Why “sneak” behaves this way
"Sneak" has an unusual and well-documented history: it was a perfectly regular verb (sneak/sneaked/sneaked) for centuries after entering English in the sixteenth century, likely from a dialectal English word related to "snike" or "snitch," meaning to creep or crawl secretly. The irregular past form "snuck" is a genuinely modern innovation, first recorded in American regional dialects in the nineteenth century and only entering mainstream, dictionary-recognized usage over the course of the twentieth century.
"Snuck" is one of the very few documented cases in English of a verb becoming irregular rather than regularizing — the opposite of the language's usual long-term drift, in which irregular verbs slowly regularize (like "help," which used to be "holp" in Middle English but is now simply "helped"). Linguists point to "snuck" as a rare counter-example precisely because it moved against the grain, likely by analogy with existing "-ing/-uck" pattern verbs like "stick/stuck" and "strike/struck," which "sneak" phonetically resembles. Corpus studies tracking American published writing across the twentieth century show "snuck" steadily rising in frequency decade by decade, overtaking "sneaked" in general American usage by around the 1990s, a shift fast enough that it has been directly observed and measured within living memory rather than reconstructed from historical records the way most irregular-verb changes must be.
The common confusion
American English has now largely normalized "snuck" in casual and even semi-formal writing, while British English still strongly prefers the historically original "sneaked" and treats "snuck" as a noticeable Americanism. Neither form is technically "wrong" by any major dictionary today, but the choice functions as a genuine dialect marker rather than a simple correctness question, unlike most irregular-versus-regular disputes on this list. This is genuinely unusual among the pairs covered on this site: in almost every other case a t-preterite or irregular variant is the older, more traditional form and the "-ed" form is the newer regularization, but here the relationship is flipped, with the irregular "snuck" being the historical newcomer and the regular "sneaked" being the older, original form.
How it's actually used
Because "snuck" still carries a whiff of informality even in American English, more traditional style guides — including many newspaper style guides — continue to specify "sneaked" for formal or hard-news writing, reserving "snuck" for quotes, dialogue, feature writing, or casual register, which makes this one of the few verbs where the "correct" choice genuinely depends on the register and audience of the piece rather than on grammar alone. Academic and legal writing almost universally defaults to "sneaked," since these registers tend to lag behind everyday speech in adopting newly popularized irregular forms, even ones as widely accepted in casual American English as "snuck" now is.
Across the tense system
Both forms behave identically in the perfect tense — "she has sneaked/snuck out before" — with no functional difference beyond register, and neither creates any ambiguity about meaning or tense. Editors generally settle on one form for a whole document rather than mixing the two, treating it the same way they'd treat a house-style choice between "smelled" and "smelt."
Common real mistakes
There isn't really a grammatical "error" here since dictionaries now list both forms, but the practical mistake many writers make is switching between "sneaked" and "snuck" inconsistently within the same document, which reads as sloppy even though each individual instance is defensible. A second, real error is the hypercorrected "snook," an occasional overcorrection from writers trying to make "snuck" sound even more irregular by analogy with "took" or "shook," which no dictionary or style guide recognizes. A third issue, more editorial than grammatical, is writers assuming "snuck" is simply wrong because an old-fashioned teacher or grammar guide once told them so; most current dictionaries, including Merriam-Webster, have listed "snuck" without any usage restriction for decades.
Examples
- She sneaked out of the house before dawn.
- He has snuck extra cookies from the jar all week.
- They sneaked past the guard without being noticed.
- The cat had snuck onto the counter again.
- We sneaked a look at the report before the meeting.
- He snuck in through the back door.
Memory trick
Think of it as a dialect dial rather than a right-or-wrong switch: American ears reach for "snuck," British ears reach for "sneaked," and both are accepted by modern dictionaries — just pick one and stay consistent within a single piece of writing.