English UsageComparison guide
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
Confusion Familyverb-complement
Rule Familyverb-complementation
Termskeen on doing, keen to do
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