English UsageComparison guide
Forget Doing vs. Forget To Do
“Forget + -ing” concerns whether an earlier event remains in memory. “Forget + to-infinitive” means the intended action was not remembered and therefore may not have been done.
“Forget doing” concerns memory of a past event. “Forget to do” means fail to remember to perform the action.
Key details
Confusion Familygrammar-and-usage distinction
Rule Familymeaning and construction
Termsforget doing, forget to do
Further guidance
Boundary
The two patterns differ in what is forgotten: a memory of an event versus the need to carry out a task.
Infinitive Pattern
Use forget + to-infinitive when someone fails to remember to perform an action.
Ing Pattern
Use forget + -ing for losing or lacking a memory of an event or experience; “never forget doing” means the memory remains.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- Forget — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Dictionary evidence for forget complementation and for the irregular forms forget, forgot, forgotten; Cambridge American usage also records forgot as a past-participle variant.