Comma with Introductory Phrases
Introductory commas mark the boundary between opening material and the main clause. Purdue OWL directly supports the comma after an introductory dependent clause; broader introductory phrases should be handled by their actual structure and clarity needs rather than by an indiscriminate “comma after every opener” rule.
Use a comma after an introductory dependent clause. Other introductory words and phrases can also take a comma when the structure or clarity calls for it, but not every short opener should be treated by one automatic rule.
Key details
Important caveats
Scope Boundary
“Introductory phrase” covers more than one structure, so avoid a mechanical rule that every short opening word or phrase must always take a comma; length, structure, clarity, and governing style can matter.
Further guidance
Application
Use a comma after an introductory dependent clause and after introductory material when the pause/boundary is needed by the applicable punctuation rule; keep the main clause easy to identify.
Core Rule
Introductory dependent clauses are followed by a comma before the independent clause.
Practical Application
Use a comma after an introductory dependent clause. For introductory words and phrases, use the comma when it marks the structure clearly or prevents misreading, while avoiding a blanket rule that every short opener must be followed by one.
Reader Check
Does the opener form a dependent clause, or would a comma materially improve the reader’s ability to see where the introduction ends and the main clause begins?
Worked Example
Write “After the meeting ended, we revised the schedule.” For a very short, unambiguous opener, follow the governing style instead of inserting a comma automatically just because the phrase comes first.
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.
- Conquering the Comma — Purdue OWL (opens in a new tab)Purdue Online Writing Lab · University writing-lab guidance showing commas after introductory dependent clauses and supporting established introductory-comma structure.