3rd grade run-on sentences worksheets

Run-on sentences worksheets for third grade print two sentences squeezed together with nothing between them. Your child finds where the first idea ends and writes in the missing period and capital letter. The choice version asks them to pick the correctly split sentence instead.

Free printable PDF worksheet, aligned to Common Core L.4.1.f.

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The kind of sentences you'll fix

Each line runs two sentences together. Add the missing period and capital letter to split them.

  1. The ice cream melted it ran down the cone.

    Fixed: The ice cream melted. It ran down the cone.

  2. The puzzle was hard we finished it anyway.
  3. The baby laughed everyone laughed too.

Every print pulls a fresh set of sentences at this level, so a make-up test or a second sibling never gets the same sheet.

What's on each sheet

Every version prints on US Letter or A4, with its answer key on the last page.

How to teach this

Teach the hunt, not the guess: find the second who-did-what pair, and the split goes right before it. Have your child read the run-on aloud in one breath. Running out of air is the body's way of finding the missing period.

Watch for: Kids split at the first breath instead of the end of the idea. Have them find the second who-did-what pair; the split goes right before it. Kids think a comma fixes a run-on. A comma alone makes a comma splice, which is still a run-on wearing a disguise. It needs a period or a comma plus a joining word.

Common questions about run-on sentences

What does my child actually write on the fix version?
The run-on prints with its period and capital missing. Your child adds both marks right on the line, and the answer key shows the corrected sentence with the added marks highlighted in green.
How do they know where to split?
Find the second who-did-what pair. In 'The cake fell the dog cheered,' the second pair is the dog cheered, so the period lands after fell. That hunt is the whole skill at this grade.

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Aligned to Common Core L.4.1.f. Reviewed by the One more sheet team. Content version 178, updated August 2026.

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