My part-time self-employment resulted in a small loss this year. Turbotax shows it as zero. Is there a reason why it does not show a loss?

In order to show a loss, you must actively participate in the business.  Check your entries to make sure you indicated that you actively participated in the business.  

To check your entries, please follow these steps:

TurboTax Online

1. In your return click on Income and Expenses and then click the Start/Revisit box in the Self-Employment section.
2. On the Your 2020 self-employed work summary screen, click on Review next to your business. 
3. On the XX's [business] info screen, in the Other situations section, make sure Yes appears below Actively participated in this work. 
4. If not, click Edit and mark the None of these apply box, and click Continue.

TurboTax CD/Download

1. Click Business > Continue > I'll choose what I work on
2. On the Let's gather your business info screen, click Update next to Business Income and Expenses.
3. On the next screen, click Edit next to your business.
4. Click the Start/Update box next to Business Profile.
5. On the screen, Let's confirm your business info, click Edit next to Special Situations.
6. On the next screen, make sure the box that says I did not actively participate... is NOT marked.
7. Click Continue.