How to Write an Introduction: Hooks, Background and Thesis

The introduction has three jobs: to attract attention, to give context, and to state your main claim. If you know those three jobs, you know how to write an introduction for almost any assignment. The UNC Writing Center's handout on introductions adds that an introduction should tell the reader what your topic is, why it is important, and how you plan to proceed with your discussion.

Many teachers explain how to write an introduction with the image of a funnel: it begins broad and narrows to your thesis. If you'd like a draft to react to, the free introduction generator writes three versions from your topic and thesis, with a choice of hook and length, and you can rework them in your own voice.

How to write a good introduction for an essay

A good introduction for an essay is short and specific. It doesn't summarize the whole paper, and it doesn't wander. For a five-paragraph essay, most teachers expect something like four to six sentences in the introduction paragraph. For a longer paper, the introduction can run a full paragraph or two. These lengths are conventions, so check your assignment sheet.

Write it last, or at least revise it last

Learning how to write an introduction includes learning when to write it. The UNC handout suggests writing your introduction last, because your argument may shift while you draft. If you need a tentative opening to get started, write one, then replace it once the body is finished. To test a draft, give the opening to a friend and ask what they expect the paper to cover. If they guess right, the introduction works.

Here is how to write an introduction for an essay in the order the reader meets it. Think of it as three layers, each narrower than the last.

The hook

The first sentence sets the tone. It should say something useful in an interesting way, which is harder than it sounds. A hook can be a scene, a question, a surprising fact or a short quotation, and the next section shows each type in action. Whichever you choose, make sure it points toward your topic.

Intro background

The next two or three sentences give the background a reader needs. Think of zooming a map: move from the wide view toward the exact issue your essay covers. The UNC handout warns against openings that are too broad to connect to the assignment, such as sweeping claims about all of human history. Add only the context a reader needs, and save the evidence for the body.

The thesis statement

End the paragraph with the thesis, the sentence that states your main argument. A strong thesis is specific and debatable, and it often includes a reason. If your wording feels loose, work it out with our thesis statement generator before you finish the opening.

A roadmap sentence

In longer essays, you can add a sentence that previews the order of your points. Skip it in a short essay, where the thesis already does the job. For a model of how the body then unfolds, see what an argumentative essay is.

Choosing a hook is often the hardest part of learning how to write an introduction. The hook is the sentence or two that makes a reader want to continue. Some teachers call it a grabber or an attention getter, and all three words mean the same thing: an opening that draws readers in. The table below compares six types. The examples that follow were written for this guide and use different topics so you can see how each hook works. If you want more ideas, the essay hook generator offers hooks by type for your own topic.

Hook sentence starters you can adapt

Hook sentence starters give you a way in when the page is blank. Try "Picture a..." or "Every morning..." for a scenario, "What if..." for a question, and "Despite..." for a fact that surprises. They work as scaffolding. In the final draft, delete any starter that sounds stiff and keep only the sentence it helped you write.

Question hooks

A question hook invites the reader into the argument. Avoid questions with a plain yes or no answer, because a reader can answer them and stop. "What would change if every student started the day well rested?" is better than "Do students need sleep?" A question hook can work best in an argumentative or persuasive essay.

Scenario and anecdotal hooks

An anecdotal hook is a very short story, often from the writer's own life or from a scene that illustrates the issue. Keep it to two sentences. If the anecdote needs more room, move it into a body paragraph and start the introduction with something shorter. A scenario hook works well in personal and reflective writing, and in essays about people.

Fact, claim and quotation hooks

A surprising fact works when it is true and checked, so cite the source in your draft. Never invent a statistic. A bold claim grabs attention but has to be defensible, because the rest of the essay must prove it. A quotation helps in literary analysis when the words really matter. In all three cases, connect the hook to your thesis within a sentence or two.

Hooks to avoid

When you study how to write an introduction, the weak openers matter as much as the strong ones. The UNC handout lists several weaker openers: a vague placeholder, a restated question, a dictionary definition, a "dawn of man" generalization, and a book-report opener that lists title, author and basic facts. Cut them from your draft.

For a sentence-level view of how to write an introduction, here is a paragraph of about five sentences. Treat it as a pattern, not a formula.

Sentence by sentence

Use this order when you want a clear plan.

1. Hook. A scene, question or fact that points toward the topic.
2. Background. What the reader needs to know about the issue.
3. Narrowing. A sentence that moves from the general issue to the specific question.
4. Thesis. Your claim and, ideally, one reason.
5. Roadmap (optional). A preview of the order of your points.

A complete sample

Here is a sample paragraph on the same topic as the page shown above, written for this guide: Every morning at 7:40, Maya locks her bike and hopes the driver beside her has seen her. Many US cities have added bike lanes, yet most main roads still make cyclists share space with traffic. That gap puts the safest option out of reach for the people who most want to use it. Cities should build protected bike lanes on main roads, because they make streets safer and replace short car trips.

Introduction templates

A template can get you started if you adapt it: "[Hook about a specific scene or question]. [Background on the issue and why it matters]. [Narrowing sentence that points to the problem]. [Thesis: claim because reason]." Fill in each bracket in your own words, then read the result aloud and cut anything that sounds like filler.

Intro ideas for different essay types

In an argumentative essay, a question or bold claim works well. In a narrative, begin with a scene. In an expository essay, a surprising fact or a plain framing of the topic often does more than a dramatic hook. Part of knowing how to write an introduction is matching the opening to the genre, so be wary of copying one that worked elsewhere.

Knowing how to write an introduction for a research paper takes a slight shift in aim, because the reader expects background and a question more than a dramatic hook. A strong research paper introduction usually makes four moves, shown on the sample page.

The four moves

First, background gives the topic and why it matters. Second, a gap or problem explains what is unknown, disputed or unresolved. Third, a research question or purpose says what your paper sets out to answer. Fourth, the thesis states your answer. A short roadmap often follows in longer papers. The UCLA Undergraduate Writing Center's handout on research paper introductions describes the same path, from the broad issue and existing research to the gap and your research question. Expectations still vary by field, so check the guidelines for your course.

Intro background for a research paper

Background is usually the longest move, and it is where learning how to write an introduction for a research paper differs most from a school essay. It should show that you know the conversation. Name the topic, cite one or two key sources and make clear why the question matters. Our guides to MLA in-text citation and APA format guidelines show how to cite those sources. For a first draft, the research paper introduction generator can lay out the pieces.

How to write an introduction for a lab report

The UNC Writing Center's scientific reports handout says a lab report introduction states the purpose of the experiment, reviews the relevant scientific literature and gives your hypothesis, with the reasons it seemed likely. Formats still vary by course, so follow your lab manual or syllabus. Keep the introduction short and move from the general idea to your specific question.

A hook in a research paper

You can still open a research paper with a hook, but make it quieter: a striking finding, a concrete case or a brief example. If your discipline prefers a plain opening, state the topic and its importance directly. Ask your instructor, or look at a published article in your field, to see which tone fits.

Connectors are a small but real part of learning how to write an introduction that flows. An introduction has to move from one layer to the next without jolts. Intro transitions are the small words and phrases that make the hook, background and thesis feel like one thought rather than three separate sentences.

Introduction transition words that work

Between the hook and the background, try "In fact," "Today," or "Across the country." To narrow the focus, use "Yet," "Still," "However," or "Even so." To lead into the thesis, try "Therefore," "For this reason," or "As a result." Use only one or two, because a transition at the start of every sentence feels mechanical.

Going deeper

Our transition words for paragraphs page sorts openers by where a paragraph sits in an essay, and the transition words tool groups connectors by purpose. For a longer list with examples, see our guide to transition words for essays.

Most weak openings come from the same few slips, so check your draft against this list. Even students who know how to write an introduction make them on a first try. The earlier table of problems and fixes shows several of them in action.

Too long or too broad

An introduction that takes a full page to reach the topic loses the reader. Cut anything that doesn't lead to the thesis. If your first sentence could begin any essay on any topic, rewrite it.

No clear thesis

If a reader finishes the introduction and can't say what you will argue, the thesis is missing or buried. Rewrite it so that it states a claim.

Promising what the essay doesn't deliver

If your thesis announces three reasons and the body proves two, change one or the other. This is the main reason to revise the introduction after the draft is done. The same applies in the other direction: your conclusion (see how to write a conclusion) should answer the question your opening raised.

Forgetting the body paragraphs

Knowing how to write an introduction only gets you started. Our guide to how to write a paragraph covers the body, where the evidence lives. When your introduction is in place, the introduction generator is a quick way to compare your version against three others, and you can browse more student writing guides for the rest of the essay.