A subordinating conjunction joins a dependent clause to an independent clause and shows how the two connect, whether by time, cause, condition, or contrast. Words like because, although, when, and if sit at the front of the weaker clause and lock it onto the main statement, turning two separate thoughts into one complex sentence.
Teaching writing for years, I keep meeting the same two hurdles: students recognise because and when, then stall on punctuation and on telling a subordinator from a coordinator. Master this compact set of connectors and the comma rule that governs them, and your sentences gain range without losing precision.
What Is a Subordinating Conjunction?
A subordinating conjunction is a word or phrase that links a dependent clause to an independent clause and marks the relationship between them. The dependent clause carries a subject and a verb, yet it never finishes a thought on its own. The independent clause stands as a full sentence. The conjunction fuses the two and signals which question the weaker clause answers about the main one: when, why, where, how, or under what condition.
Take two full sentences: The power went out. We lit candles. Drop when in front of the first and the balance shifts: When the power went out, we lit candles. One thought now depends on the other, and the reader knows exactly how they relate.
Every subordinator does two jobs at once. It bridges the two clauses, and it ranks them, pushing the main statement forward and holding the supporting statement back in the dependent clause.
Subordinating Conjunctions List
Most subordinators belong to a compact set worth memorising. Some stand as single words; others work as fixed phrases of two or three words that behave as one connector.
One-Word Subordinating Conjunctions
After, although, as, because, before, if, once, since, than, that, though, till, unless, until, when, whenever, where, wherever, while.
A few earn extra attention. Since and as swing between time and cause, so the surrounding words decide the meaning: since Monday marks time, since you asked marks reason. That introduces clauses so quietly that writers forget it counts as a subordinator. Than links the two halves of a comparison and nothing else.
Compound Subordinating Conjunctions
Several subordinators run as fixed phrases. They join clauses the same way single words do, and they never split apart:
As soon as, as long as, as though, as if, even if, even though, in case, in order that, provided that, so that, now that, rather than, by the time.
Even though and even if look alike but part ways in meaning. Even though concedes a fact (even though it rained, we walked), while even if proposes a condition (even if it rains, we walk). So that signals purpose, which separates it from the coordinating so that signals result.
Types of Subordinating Conjunctions by Function
Subordinators earn their keep by naming the relationship between two clauses. Eight relationships cover almost everything you write.
| Function | Common subordinators | Sample sentence |
|---|---|---|
| Time | After, before, when, while, until, since, as soon as | We ate after the guests arrived. |
| Place | Where, wherever | Sit wherever you find room. |
| Cause and reason | Because, since, as | She left early because her shift ended. |
| Purpose | So that, in order that | He whispered so that no one would hear. |
| Condition | If, unless, provided that, in case | You pass unless you skip the exam. |
| Contrast and concession | Although, though, even though, whereas, while | Although he trained hard, he lost. |
| Comparison | Than, as, as though | She runs faster than he does. |
| Manner | As, as if, as though | He spoke as if he owned the place. |
Several words appear under more than one relationship. While marks time (while you sleep) and contrast (while I agree, I hesitate). As stretches across time, cause, comparison, and manner. Read the whole clause before you label the conjunction, since the surrounding words fix its job.
Comma Rules for Subordinating Conjunctions
Punctuation follows one question: which clause comes first? Position decides the comma.
When the dependent clause opens the sentence, close it with a comma before the main clause:
- Because the road flooded, we turned back.
- Although she apologised, he stayed angry.
When the main clause opens and the dependent clause trails, drop the comma:
- We turned back because the road flooded.
- He stayed angry although she apologised.
✅ Comma test: front-load the dependent clause and you need a comma; trail it behind the main clause and you do not.
One exception earns a second look. Contrast and concession subordinators (although, though, whereas, while) frequently take a comma even in the trailing position, because the shift in meaning wants a pause: He kept smiling, though his patience had run out. Read the sentence aloud; a genuine break in thought signals the comma.
Where to Place a Subordinating Conjunction in a Sentence
A stubborn myth says a sentence must never open with a subordinating conjunction. It opens with one all the time, and doing so is correct English. Placement changes emphasis, not grammar.
Lead with the dependent clause to foreground the condition or cause:
- Until you finish your chores, the game stays off.
Trail the dependent clause to foreground the result or main action:
- The game stays off until you finish your chores.
Both sentences carry the same meaning. The front position stresses the setup; the back position stresses the outcome. Choose the order that matches the emphasis you want.
Subordinating Conjunctions in Complex and Compound-Complex Sentences
A subordinating conjunction drives the complex sentence: one independent clause plus at least one dependent clause.
- When the bell rang, the students filed out.
Add a second independent clause joined by a coordinator, and the sentence turns compound-complex, holding two independent clauses and at least one dependent clause:
- When the bell rang, the students filed out, but the teacher stayed behind.
Here when the bell rang is the dependent clause, the students filed out and the teacher stayed behind are independent clauses, and but coordinates the two independent halves. Writers reach for compound-complex sentences to pack related events into one controlled line rather than three short ones.
Subordinating vs Coordinating Conjunctions
Both kinds join clauses, yet they rank them differently. A Coordinating Conjunction (the FANBOYS: for, and, nor, but, or, yet, so) links two equal independent clauses. A subordinating conjunction links unequal clauses, bending one into a dependent role.
| Feature | Subordinating conjunction | Coordinating conjunction |
|---|---|---|
| Joins | Dependent clause to independent clause | Two independent clauses |
| Clause rank | Unequal, one depends on the other | Equal |
| Sample words | Because, although, when, if, since | For, and, nor, but, or, yet, so |
| Comma | When the dependent clause leads | Before the conjunction between two independent clauses |
She stayed home because she felt ill subordinates the reason to the main action. She felt ill, so she stayed home gives both clauses equal weight and joins them with a coordinator. The meaning overlaps; the grammar and the emphasis differ.
Subordinating Conjunctions vs Conjunctive Adverbs
Words like however, therefore, moreover, and consequently feel like conjunctions, yet they are conjunctive adverbs, and they do not grammatically join two clauses. Wire two independent clauses together with one and you create a comma splice.
- ❌ She trained hard, however she lost.
- ✅ She trained hard; however, she lost.
- ✅ She trained hard. However, she lost.
A subordinating conjunction fuses its clause to the main clause inside one sentence. A conjunctive adverb sits between two independent statements and takes a semicolon or a period, plus a comma of its own. The test: a true subordinator answers when, why, or under what condition; a conjunctive adverb marks a transition without binding the grammar.
Subordinating Conjunction or Preposition?
Several time words (after, before, since, until, as) live a double life as prepositions. The difference rests on what follows the word, not the word itself.
Followed by a full clause with its own subject and verb, the word works as a subordinating conjunction:
- After the movie ended, we walked home. Here the movie ended is a clause.
Followed by a noun or noun phrase alone, the same word works as a preposition:
- After the movie, we walked home. Here the movie is a noun phrase.
Check for a subject and verb behind the word. A clause behind it means a conjunction; a noun phrase means a preposition.
Common Mistakes With Subordinating Conjunctions
A handful of errors recur across student writing.
Comma dropped when the dependent clause leads. A front-loaded clause needs its comma.
- ❌ Because it rained we cancelled the match.
- ✅ Because it rained, we cancelled the match.
Wrong subordinator for the relationship. The conjunction has to match the logic. Unless sets a condition, not a cause.
- ❌ We stayed inside unless it was raining.
- ✅ We stayed inside because it was raining.
Fragment left standing. A dependent clause on its own is a sentence fragment.
- ❌ Although she studied for weeks.
- ✅ Although she studied for weeks, she still failed the test.
Coordinator mistaken for subordinator. So signals result and coordinates; so that signals purpose and subordinates. Swapping them shifts the meaning.
- ✅ He left early so he caught the bus. (result)
- ✅ He left early so that he would catch the bus. (purpose)
Subordinating Conjunctions in Sentences
Reading subordinators inside full sentences trains the ear faster than any rule. The conjunction is bold in each.
- Because the flight was delayed, we missed the connection.
- We kept the windows open until the storm rolled in.
- Although the reviews were harsh, the film sold out.
- She signs every card as if her name were a work of art.
- Unless the numbers improve, the project stalls.
- He saved for a year so that he would travel through Japan.
- Wherever the trail forked, they chose the steeper path.
- I trust her judgement more than I trust my own.
FAQs
A subordinating conjunction is a word or phrase that joins a dependent clause to an independent clause and shows their relationship, whether time, cause, condition, or contrast. Words such as because, although, when, and if introduce the dependent clause and build a complex sentence.
The frequent ones include after, although, as, because, before, if, once, since, than, that, though, unless, until, when, where, and while, along with phrases like even though, so that, and as soon as.
Position decides. When the dependent clause opens the sentence, place a comma before the main clause: Because it rained, we stayed in. When the dependent clause follows the main clause, drop the comma: We stayed in because it rained. Contrast words like although frequently keep a comma even when they trail.
Yes. Opening a sentence with because, although, when, or if is correct, as long as a comma separates the dependent clause from the main clause. The old warning against it is a myth.
A subordinating conjunction joins unequal clauses, making one depend on the other. A coordinating conjunction (the FANBOYS: for, and, nor, but, or, yet, so) joins two equal independent clauses. Subordinators build complex sentences; coordinators build compound ones.
Yes. Because ranks among the most common subordinating conjunctions, and it marks cause and effect: She left because she was tired. On its own, a clause starting with because stays incomplete.
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