Be Keen On Doing vs. Keen To Do
Oxford directly documents keen on doing and keen to do. Both can express eagerness; the page therefore avoids inventing a rigid meaning split that the cited dictionary does not require.
Both “keen on doing” and “keen to do” are standard. Oxford documents both for eagerness or enthusiasm, so choose the structure that fits the sentence rather than treating one as ungrammatical.
Key details
Choose the right form
| Meaning / situation | Construction | Decision |
|---|---|---|
| enthusiasm directed toward an activity treated as a topic or pursuit | keen on + -ing | use the gerund construction |
| eagerness or willingness to take an action | keen + to-infinitive | use the infinitive construction |
Quick tests
Activity-or-action test
Is the sentence treating the activity as something the person is enthusiastic about, or expressing eagerness to perform an action?
If yes: Use “keen on + -ing” for the activity/topic pattern.
If no: Use “keen to + verb” for the infinitive action pattern.
Caveat: Oxford documents both forms for eagerness; do not invent a rigid semantic rule where context allows overlap.
Examples
She is keen on learning new languages.
The gerund phrase presents the activity as an object of enthusiasm.
She is keen to learn more about the role.
The infinitive presents the action she is eager to take.
Both forms can express enthusiasm, so choose the structure that fits the sentence rather than treating either as inherently wrong.
The distinction is grammatical and contextual, not a blanket correctness split.
Further guidance
Core difference
Both complement patterns are documented: keen on + -ing and keen + to-infinitive.
Style Boundary
Do not label either pattern universally wrong or infer a stronger semantic contrast than the authority supports.
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.
- keen adjective — Oxford Advanced Learner’s Dictionary (opens in a new tab)Oxford University Press · Preferred-dictionary evidence for both keen on doing and keen to do constructions