Americans who say they expect to "never retire" are more likely than others to score low on a measure of financial knowledge, a new study shows.

In a national survey, 20% of those who missed all three financial knowledge questions said they expected they would never retire, compared to 12% who answered all questions correctly, who said they'd likely work well past retirement age.

The study also found that those who were overconfident in their financial knowledge (and those whose low levels of confidence reflected their knowledge) were more likely to say they would never retire.

The findings, combined with other research, suggest that many people who say they will never retire aren't saying that because they love their jobs and want to continue working indefinitely, said Sherman Hanna, co-author of the study and professor of consumer sciences at The Ohio State University.

"If you're not knowledgeable about finances, it suggests that you don't know what your financial situation is, and you may have no idea when you can retire," Hanna said.

• Read More