Snack bars with healthy-sounding names and pictures of fruit on the packaging often trick customers into thinking they contain real fruit.
Australian consumer group Choice analysed more than 200 snack bars and found many contain no fruit at all.
Spokesperson Tom Godrey says parents should avoid getting sucked in by marketing hype.
"Time-poor parents choose these thinking it's a healthy choice, but in actual fact there's little to no fruit in these products."
He says to be aware of terms such as "natural", "low-fat" and "low GI".
Kellogg's, one of the companies accused of misleading parents in the report, said it had recently redesigned much of its packaging to avoid showing too much fruit - particularly its K-Time Twists bars.
"Our new packaging clearly says the product is raspberry and apple flavour," the company told the Sydney Morning Herald.
"We are not suggesting they are a replacement for fruit. Any images of fruit are to show the flavour you can expect."
But Australian obesity campaigner Jane Martin told the paper such images are clearly misleading.
"The use of a real raspberry on a product suggests to consumers that the product contains real fruit. At a time when 63 percent of Australian adults and 27 percent of children are overweight or obese, we want to see food manufacturers adopt the health star rating system to help consumers make more informed food choices."
Kellogg's recently rolled out health star ratings on many of its products, all of which are available on the company's website.
Last year it even changed the recipe of one of its products - Nutri-Grain Original - to get a better score.