How to Write Topic Sentences | 4 Steps, Examples & Purpose

Every paragraph in your paper needs a topic sentence. The topic sentence expresses what the paragraph is about. It should include two key things:

• The topic of the paragraph
• The central point of the paragraph.

After the topic sentence, you expand on the point with evidence and examples.

To build a well-structured argument, you can also use your topic sentences to transition smoothly between paragraphs and show the connections between your points.

Writing strong topic sentences

Topic sentences aren’t the first or the last thing you write—you’ll develop them throughout the writing process. To make sure every topic sentence and paragraph serves your argument, follow these steps.

Step 1: Write a thesis statement

The first step to developing your topic sentences is to make sure you have a strong thesis statement. The thesis statement sums up the purpose and argument of the whole paper.

Step 2: Make an essay outline and draft topic sentences

Next, you should make an outline of your essay’s structure, planning what you want to say in each paragraph and what evidence you’ll use.

At this stage, you can draft a topic sentence that sums up the main point you want to make in each paragraph. The topic sentences should be more specific than the thesis statement, but always clearly related to it.

Step 3: Expand with evidence

The rest of the paragraph should flow logically from the topic sentence, expanding on the point with evidence, examples, or argumentation. This helps keep your paragraphs focused: everything you write should relate to the central idea expressed in the topic sentence.

In our example, you might mention specific research studies and statistics that support your point about the overall impact of the meat industry.

Step 4: Refine your topic sentences

Topic sentences usually start out as simple statements. But it’s important to revise them as you write, making sure they match the content of each paragraph.

A good topic sentence is specific enough to give a clear sense of what to expect from the paragraph, but general enough that it doesn’t give everything away. You can think of it like a signpost: it should tell the reader which direction your argument is going in.

To make your writing stronger and ensure the connections between your paragraphs are clear and logical, you can also use topic sentences to create smooth transitions.

Topic sentences as transitions between paragraphs

As you write each topic sentence, ask yourself: how does this point relate to what you wrote in the preceding paragraph? It’s often helpful to use transition words in your topic sentences to show the connections between your ideas.

Emphasize and expand

If the paragraph goes into more detail or gives another example to make the same point, the topic sentence can use words that imply emphasis or similarity (for example, furthermore, indeed, in fact, also).

Indeed, cattle farming alone is responsible for a large proportion of greenhouse gas emissions.

Summarize and anticipate

If the paragraph turns to a different aspect of the same subject, the topic sentence can briefly sum up the previous paragraph and anticipate the new information that will appear in this one.

While beef clearly has the most dramatic footprint, other animal products also have serious impacts in terms of emissions, water and land use.

Compare and contrast

If the paragraph makes a comparison or introduces contrasting information, the topic sentence can use words that highlight difference or conflict (for example, in contrast, however, yet, on the other hand).

However, the environmental costs of dietary choices are not always clear-cut; in some cases, small-scale livestock farming is more sustainable than plant-based food production.

You can also imply contrast or complicate your argument by formulating the topic sentence as a question.

Is veganism the only solution, or are there more sustainable ways of producing meat and dairy?

Topic sentences that introduce more than one paragraph

Sometimes you can use a topic sentence to introduce several paragraphs at once.

All of the examples above address the environmental impact of meat-eating versus veganism. Together, they make up one coherent part of a larger argument, so the first paragraph could use a topic sentence to introduce the whole section.

Where does the topic sentence go?

The topic sentence usually goes at the very start of a paragraph, but sometimes it can come later to indicate a change of direction in the paragraph’s argument.

Given this evidence of the meat industry’s impact on the planet, veganism seems like the only environmentally responsible option for consumers. However, the environmental costs of dietary choices are not always clear-cut; in some cases, small-scale livestock farming is more sustainable than plant-based food production.

In this example, the first sentence summarizes the main point that has been made so far. Then the topic sentence indicates that this paragraph will address evidence that complicates or contradicts that point.

In more advanced or creative forms of academic writing, you can play with the placement of topic sentences to build suspense and give your arguments more force. But if in doubt, to keep your paper clear and focused, the easiest method is to place the topic sentence at the start of the paragraph.

View topic sentences in an example essay

Frequently asked questions about topic sentences

What is a topic sentence?

A topic sentence is a sentence that expresses the main point of a paragraph. Everything else in the paragraph should relate to the topic sentence.

Why are topic sentences important?

Topic sentences help keep your writing focused and guide the reader through your argument.

In an essay or paper, each paragraph should focus on a single idea. By stating the main idea in the topic sentence, you clarify what the paragraph is about for both yourself and your reader.

Where does the topic sentence go in a paragraph?

The topic sentence usually comes at the very start of the paragraph.

However, sometimes you might start with a transition sentence to summarize what was discussed in previous paragraphs, followed by the topic sentence that expresses the focus of the current paragraph.

What are some examples of topic sentences?

Let’s say you’re writing a five-paragraph essay about the environmental impacts of dietary choices. Here are three examples of topic sentences you could use for each of the three body paragraphs:

1. Research has shown that the meat industry has severe environmental impacts.
2. However, many plant-based foods are also produced in environmentally damaging ways.
3. It’s important to consider not only what type of diet we eat, but where our food comes from and how it is produced.

Each of these sentences expresses one main idea – by listing them in order, we can see the overall structure of the essay at a glance. Each paragraph will expand on the topic sentence with relevant detail, evidence, and arguments.