Topic Sentences

What is a topic sentence?

The function of a topic sentence is to introduce the idea that you are going to discuss in that particular paragraph.

Topic sentence definition:

A topic sentence is a statement that expresses the main idea of a paragraph or other section of writing.


Topic sentences are usually provided at the beginning of each new paragraph in your essay.

Writing a topic sentence

In order to write a topic sentence, you will first need to know what ideas you are going to write about in each paragraph.

For this reason, students sometimes find it easier just to begin writing each paragraph before writing the topic sentences.

Writing the body of the paragraph in this way will help to make clear in your mind what precise point you are going to express.

Once you have written the main body sentences, you can then go back and write or revise your topic sentences.

Topic sentence exercise

Let’s consider the topic of our expository essay assignment: Should the government offer more forms of financial aid to college students?

You will recall that when you write your main body paragraphs, you need to make a list of the reasons why you support or oppose increased financial aid.

You will then group your reasons into three main topics and write each paragraph from your notes.

Please see our separate section on writing the main body for more information.

For the purposes of this exercise, we are including some sample main body paragraphs below.

Instructions: Read each paragraph, and then try to write a topic sentence that introduces each one. Then study the examples below.

______________________. Capable students who would like to further their education may not be able to do so simply because they cannot afford to pay the tuition. Potential college candidates may also be dissuaded by the related educational expenses, such as the cost of books and other fees.

______________________. Many college applicants do not come from well-off families. If the government does not offer increased financial support to those who need it most, access to institutions of higher education will be distributed unequally in favor of those from the highest socioeconomic levels of society.

______________________. The government needs to consider the question: Who will be the leaders of tomorrow? Increased educational opportunities go hand in hand with improved funding, resulting in a better educated population, and better educated citizens help to bring about social change and cultural improvements for everyone.

Topic sentence examples

Study the topic sentences in italics in the paragraphs reproduced below.


Potential students may not be able to attend college simply because of the cost. Capable students who would like to further their education may not be able to do so simply because they cannot afford to pay the tuition. Potential college candidates may also be dissuaded by the related educational expenses, such as the cost of books and other fees.

Access to education predominantly to those from upper income categories encourages the education of a privileged elite. Many college applicants do not come from well-off families. If the government does not offer increased financial support to those who need it most, access to institutions of higher education will be distributed unequally in favor of those from the highest socioeconomic levels of society.

Providing increased financial support also helps to ensure the future progress of society. The government needs to consider the question: Who will be the leaders of tomorrow? Increased educational opportunities go hand in hand with improved funding for college, resulting in a better educated population, and better educated citizens help to bring about social change and cultural improvements for everyone.

Now try the exercises on paragraphing and writing the conclusion.