Writing Topic Sentences — Purpose, Structure, and Examples

A topic sentence in academic writing identifies how a body paragraph relates to the overall purpose of an essay stated in the thesis statement. Topic sentences are usually at the beginning of a paragraph and identify the paragraph’s controlling idea.

While an essay’s thesis statement identifies the point of the essay in its entirety, the topic sentence has a much narrower focus, as it relates only to the paragraph in which it is located.

What is the purpose of a topic sentence?

• Makes a claim
• Supports other claims made in the paper
• Identifies the purpose of the rest of the paragraph
• Relates the paragraph to the purpose of the paper
• Precedes information that defends a claim

How to write a topic sentence

To write a topic sentence, incorporate the following guidelines:

1. Determine the thesis of the essay.
2. Identify the main supports that help prove the thesis.
3. Use each main support to structure a topic sentence for each paragraph.
4. Compose a sentence that answers the following questions:
   • What will the paragraph prove?
   • How does the paragraph connect to the thesis?

Where is the topic sentence in a paragraph?

Topic sentences can be placed at the beginning or end of a paragraph.

• Although it does not need to be the first sentence, the topic sentence should be placed at the beginning of the paragraph so the reader can quickly identify the purpose of the paragraph.
• While not a common placement for a topic sentence, some writers use topic sentences at the end of a paragraph. Writers who choose this method want the reader to deduce the main point of the paragraph by presenting the evidence first.

Topic sentence examples

The following list identifies topic sentences based on the provided thesis statements for five-paragraph essays:

Thesis Statement: Capital punishment should be banned because it is inhumane, unconstitutional, and ineffective at deterring crime.

• Support Paragraph 1 Topic Sentence: The inhumane nature of the death penalty proves it should be abolished.
• Support Paragraph 2 Topic Sentence: Capital punishment should be outlawed because it violates the Constitution.
• Support Paragraph 3 Topic Sentence: Because the death penalty does not effectively deter criminal behavior, states should not continue to use it.

Thesis Statement: College athletes should be financially compensated because they sacrifice their minds and bodies, cannot hold an outside job, and increase the school’s revenue.

• Support Paragraph 1 Topic Sentence: Student athletes should be paid for their performance because of sports’ impact on their minds and bodies.
• Support Paragraph 2 Topic Sentence: Because most college athletes cannot play their sport and hold a job, colleges should give them a living wage.
• Support Paragraph 3 Topic Sentence: Student-athletes’ ability to increase their college’s revenue proves they should be awarded financial compensation.

Thesis Statement: Using alternative energy sources can help lessen the impact of global climate change.

• Support Paragraph 1 Topic Sentence: Through the widespread use of solar power, countries can limit the environmental impact of other energy sources.
• Support Paragraph 2 Topic Sentence: Utilizing more wind turbines as a power source can help mitigate the effects of climate change.
• Support Paragraph 3 Topic Sentence: Using geothermal power will effectively decrease the world's reliance on fossil fuels.