Rely On Doing vs. Rely To Do
Cambridge documents rely on/upon with -ing clauses and also “rely on someone/something to do something.” A sentence such as “rely on the team to deliver” is valid and is structurally different from bare “rely to deliver.”
Use “rely on doing” when the relied-on basis is an action or event; bare “rely to do” is not the corresponding direct pattern.
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| depend on an action, process, or event | rely on + -ing | Use the preposition “on” before the -ing activity. |
| depend on a person or thing | rely on/upon + noun | Name the person or thing after the documented preposition. |
| use bare “rely to do” as the equivalent complement | not the documented parallel pattern | Do not drop “on” and substitute a direct infinitive. |
Quick tests
Meaning / construction test
Are you naming the action or event that provides the basis for dependence?
If yes: Use “rely on doing.”
If no: If you are naming a person or thing, use “rely on/upon” plus that noun; bare “rely to do” is not the parallel complement.
Examples
We rely on checking the figures twice before publication.
“On” introduces the activity the process depends on.
The team relies on regular backups.
A noun phrase can follow the same preposition.
You cannot rely on remembering every detail without notes.
The -ing clause names the action being depended on.
Further guidance
Boundary
A sentence such as “rely on the team to deliver” is valid and is structurally different from bare “rely to deliver.”
Construction
Cambridge documents rely on/upon with -ing clauses and also “rely on someone/something to do something.”
Decision
Use “rely on doing” when the relied-on basis is an action or event; bare “rely to do” is not the corresponding direct pattern.
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.
- rely on/upon someone/something — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Rely on/upon supports -ing clauses and the distinct pattern rely on someone/something to do something.