ACT English · Punctuation

Semicolons on the ACT: Every Rule, Named and Explained

Semicolons do three things on the ACT: connect independent clauses, connect independent clauses with words like “however” after the semicolon, and act as a super-comma. Semicolons are very easy once you understand the rules; the ACT often tricks students into selecting a semicolon because it “looks sophisticated,” even if it is not correct. If you learn the rules on this page, you should always answer semicolon questions on the ACT correctly.

Rules covered in this guide

Rule	Named Method	Frequency
Semicolon joining two independent clauses	The Period Test	Very High
Semicolon + conjunctive adverb (however, therefore, etc.)	The Conjunctive Adverb Check	Very High
Semicolons in complex lists (the super-comma)	The Internal Comma Scan	Low
When NOT to use a semicolon: before a dependent clause	The Subordinator Scan	Medium
When NOT to use a semicolon: before a FANBOYS conjunction	The FANBOYS Firewall	High

Rule 1

Semicolons Joining Two Independent Clauses

Very High Frequency

A semicolon can join two independent clauses — and nothing else. Both the clause before the semicolon and the clause after it must be able to stand alone as complete sentences. If either side is a fragment or a dependent clause, the semicolon is wrong.

Named Method

The Period Test

Replace the semicolon with a period. Read both halves as separate sentences. If both sentences are grammatically complete and make sense on their own, the semicolon is correct. If either half falls apart — becomes a fragment or fails to make sense — the semicolon is wrong.

This works because a semicolon is grammatically identical to a period. The only difference is that a semicolon signals the two ideas are closely related. On the ACT, if a period works, a semicolon works. If a period doesn’t work, neither does a semicolon.

✓ Correct

The experiment yielded unexpected results; the team immediately scheduled a follow-up study.

✗ Incorrect — fragment after semicolon

The experiment yielded unexpected results; causing the team to schedule a follow-up study.

ACT-style practice question

The city had invested heavily in its public transit system for decades, as a result ridership had grown to record levels by the end of the century.

A. NO CHANGE

B. ; as a result, ridership

C. , as a result, ridership

D. ; as a result ridership

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Rule 2

Semicolons with Conjunctive Adverbs (However, Therefore, and More)

Very High Frequency

When a conjunctive adverb — a word like “however,” “therefore,” “furthermore,” “nevertheless,” “consequently,” or “moreover” — connects two independent clauses, it must be preceded by a semicolon and followed by a comma. This is a fixed, testable pattern on the ACT: semicolon + conjunctive adverb + comma.

Named Method

The Conjunctive Adverb Check

When you see a word like “however,” “therefore,” “furthermore,” “nevertheless,” “consequently,” or “moreover” in an underlined portion, immediately check what comes before it and after it. The pattern must be: independent clause + semicolon + conjunctive adverb + comma + independent clause.

Conjunctive adverbs are not FANBOYS. They cannot join two independent clauses with just a comma. A comma before “however” creates a comma splice. A period before “however” is grammatically fine but removes the relationship signal. On the ACT, the semicolon version is almost always the answer when both independent clauses are present.

✓ Correct

The senator supported the bill; however, she had reservations about one specific provision.

✗ Incorrect — comma splice

The senator supported the bill, however, she had reservations about one specific provision.

ACT-style practice question

The researchers had expected the new compound to be unstable; therefore, it came as a surprise when the molecule held its structure under extreme heat.

A. NO CHANGE

B. , therefore, it

C. ; therefore it

D. , therefore it

Rule 3

Semicolons in Complex Lists (The Super-Comma)

Low Frequency

When items in a list already contain commas within them, use semicolons — not commas — to separate the items. This prevents the reader from confusing the commas inside the items with the commas separating the items. This use of the semicolon is called the “super-comma,” and it is the only time a semicolon does not require an independent clause on each side.

Named Method

The Internal Comma Scan

When you see a list in a sentence, scan each item for internal commas. If any item in the list already contains a comma (for example, a city and state, a name and title, or a date), the items must be separated by semicolons rather than commas.

This is the one exception to the rule that semicolons require independent clauses. The super-comma use is about clarity, not clause structure. If you see a list with semicolons separating items, do not apply the Period Test — it does not apply here.

✓ Correct — super-comma

The tour stopped in Austin, Texas; Nashville, Tennessee; and Atlanta, Georgia.

✗ Incorrect — confusing commas

The tour stopped in Austin, Texas, Nashville, Tennessee, and Atlanta, Georgia.

ACT-style practice question

The conference featured presentations by Dr. Elena Marsh, a marine biologist; Dr. James Okafor, an atmospheric scientist, and Dr. Priya Suresh, a glaciologist.

A. NO CHANGE

B. Dr. James Okafor, an atmospheric scientist and

C. Dr. James Okafor an atmospheric scientist, and

D. Dr. James Okafor, an atmospheric scientist; and

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Rule 4

When NOT to Use a Semicolon: Before a Dependent Clause

Medium Frequency

A semicolon requires an independent clause on both sides. A dependent clause — one that begins with a subordinating conjunction like “because,” “although,” “since,” “when,” “while,” “if,” or “unless” — cannot follow a semicolon. This is the most common semicolon trap on the ACT: the semicolon looks sophisticated, and students select it without checking whether what follows is truly independent.

Named Method

The Subordinator Scan

Before choosing a semicolon answer on the ACT, scan the word immediately after the semicolon. If that word is a subordinating conjunction — “because,” “although,” “since,” “when,” “while,” “if,” “unless,” “after,” “before,” or “even though” — the semicolon is wrong. A dependent clause cannot follow a semicolon.

Apply the Period Test: replace the semicolon with a period and read what follows as a standalone sentence. If it begins with “Because…” or “Although…” and has nothing before it, it fails as a sentence — which means the semicolon fails too.

✗ Incorrect — dependent clause after semicolon

The project was cancelled; because the funding had been withdrawn at the last minute.

✓ Correct — no semicolon needed

The project was cancelled because the funding had been withdrawn at the last minute.

ACT-style practice question

The hiking trail had been closed for most of the summer; although the damage from the spring floods was more extensive than park rangers had initially reported.

A. NO CHANGE

B. , although, the damage

C. , although the damage

D. ; although, the damage

Rule 5

When NOT to Use a Semicolon: Before a FANBOYS Conjunction

High Frequency

A semicolon is never used directly before a FANBOYS conjunction — for, and, nor, but, or, yet, so. These coordinating conjunctions join clauses with a comma before them, not a semicolon. A semicolon before “but,” “and,” or “so” is always wrong on the ACT, even when both sides are independent clauses.

Named Method

The FANBOYS Firewall

When you see a semicolon immediately before a FANBOYS word — for, and, nor, but, or, yet, so — it is always wrong. No exceptions on the ACT. The correct punctuation before a FANBOYS conjunction joining two independent clauses is a comma, not a semicolon.

A quick way to remember this: semicolons and FANBOYS conjunctions are doing the same job — joining independent clauses — so they never appear together. You pick one or the other. Semicolon alone, or comma + FANBOYS. Never semicolon + FANBOYS.

✗ Incorrect — semicolon before FANBOYS

The museum had extended its hours; but attendance remained lower than expected.

✓ Correct — comma before FANBOYS

The museum had extended its hours, but attendance remained lower than expected.

ACT-style practice question

The engineering team had tested the prototype under controlled conditions; and the results exceeded every benchmark they had set at the beginning of the project.

A. NO CHANGE

B. , and, the

C. ; but the

D. , and the

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Quick-Reference Summary: All 5 ACT Semicolon Rules

Rule	Named Method	Frequency
Semicolon joining two independent clauses	The Period Test	Very High
Semicolon + conjunctive adverb (however, therefore, etc.)	The Conjunctive Adverb Check	Very High
Semicolons in complex lists (the super-comma)	The Internal Comma Scan	Low
When NOT to use a semicolon: before a dependent clause	The Subordinator Scan	Medium
When NOT to use a semicolon: before a FANBOYS conjunction	The FANBOYS Firewall	High

How to Approach Semicolon Questions on Test Day

Tip 1

Always apply the Period Test first. Before you choose any answer that includes a semicolon, replace the semicolon with a period and read both halves as separate sentences. If both sides work as standalone sentences, the semicolon is a valid option. If either side fails, eliminate that answer immediately — no exceptions.

Tip 2

Scan the word immediately after the semicolon. If the next word is a FANBOYS conjunction (and, but, or, so, yet, for, nor), eliminate that answer immediately — semicolon + FANBOYS is always wrong. If the next word is a subordinating conjunction (because, although, since, when, while), eliminate it too — a semicolon before a dependent clause is always wrong.

Common Questions About ACT Semicolon Rules

If a semicolon and a period do the same thing, how do I know which one the ACT wants when both are answer choices? +

When a semicolon and a period are both answer choices and both are grammatically correct, look at the other options. The ACT almost never presents two correct answers — if one is wrong for a different reason (wrong comma placement, dependent clause issue, etc.), the other is the answer.

In the rare case where a period answer and a semicolon answer are both clean and grammatically identical, the ACT typically prefers the semicolon when the two clauses are closely related in meaning, and the period when they feel more separate. But in practice, this exact scenario is uncommon — one of the two options almost always has an additional error that eliminates it.

Can I use a semicolon before “however” or “therefore” — or do I need a comma there? +

Semicolon before, comma after — every time. “However,” “therefore,” “furthermore,” “nevertheless,” and similar conjunctive adverbs always follow this exact pattern when they connect two independent clauses: independent clause; conjunctive adverb, independent clause.

A comma before “however” is a comma splice — always wrong. A semicolon before “however” with no comma after it is also wrong. Both pieces of punctuation are required. The full pattern must be present.

Note: if “however” appears in the middle of a sentence as a parenthetical — not connecting two clauses — it gets commas on both sides, like a comma sandwich: “The results, however, were inconclusive.” That is a different situation entirely.

How do I quickly tell if what comes after the semicolon is actually an independent clause when the sentence is really long? +

Use a pencil and physically cross out everything that is not the main subject and main verb of the clause after the semicolon. Long ACT sentences are designed to confuse you with modifying phrases, appositives, and prepositional phrases that bury the clause structure. Strip them out.

Then ask two questions: Does what remains have a subject? Does it have a verb? If yes to both, and it is not introduced by a subordinating conjunction, it is an independent clause and the semicolon is valid. If it is missing a subject, missing a verb, or starts with “because” or “although,” it is not independent — and the semicolon is wrong.

What are the specific ways the ACT tries to trick you with a semicolon that looks correct but is wrong? +

There are three main semicolon traps the ACT uses repeatedly:

Trap 1 — Semicolon before a dependent clause. The ACT places a semicolon before “because,” “although,” or “since” and bets that you will not check whether the second half is truly independent. It sounds sophisticated. It is wrong.

Trap 2 — Semicolon before a FANBOYS conjunction. “The results were promising; but the funding ran out.” Students who know that both sides are independent clauses sometimes reach for the semicolon — but FANBOYS conjunctions take a comma, not a semicolon.

Trap 3 — Semicolon before a participial phrase. “The committee adjourned the meeting; having reached a unanimous decision.” The phrase after the semicolon has no subject — “having reached” is a participial phrase, not an independent clause. The Period Test exposes this immediately: “Having reached a unanimous decision.” is not a sentence.

Is there any situation on the ACT where a semicolon and a colon are both grammatically correct? +

Technically yes, but the ACT is designed so that only one answer is correct — so in practice, no. Here is the difference: a colon introduces something that follows from the first clause, such as a list, an explanation, or a restatement. A semicolon connects two equally weighted independent clauses without implying that the second explains or restates the first.

If the second clause explains, defines, or lists what the first clause introduced, a colon is correct and a semicolon is not. If the two clauses are simply related but neither explains the other, a semicolon is correct and a colon is not. The ACT will write the sentence so that only one of these relationships is true — leaving only one correct answer.