McDonald's wants to open a 24-hour restaurant and drive-through at the former Ty Glas pub in Llanishen.
Opponents say it is just 200m away from Coed Glas Primary School and opposite a leisure centre.
McDonald's has moved to allay fears about unhealthy food and smells, while planning officers are recommending councillors approve the plan next week.
Coed Glas head teacher Kevin Hart told Cardiff Council: "The proposal to establish a McDonald's so close to the school is a significant concern, particularly as there is already a fish and chip takeaway in Llanishen village.
"Furthermore, I am very concerned that agreeing to a fast-food establishment on a residential estate may well lead to an increase in anti-social behaviour in the evenings."
Mr Hart also raised concerns about extra traffic, while other people have expressed fears about litter, noise and odour.
Opponents have also pointed to research suggesting a connection between obesity in children and the proximity of fast-food restaurants to schools.
A total of 19 people have written in support of the proposed new outlet, which is promised to create 65 jobs, according to the Local Democracy Reporting Service.
Cardiff Council officers say the use of the former pub to provide food and drink "is established and lawful" and is not a matter for consideration by the planning committee.
The officers did not believe the extra traffic would affect road safety, and thought more than enough litter bins were proposed.
In a statement to the council, McDonald's said its restaurants had air extraction systems which remove 98% of airborne grease at source, and the firm was "committed to supporting its customers to make dietary choices that are right for them".
The company said it was doing this by reducing fats and sugars in its products, broadening the menu choice, and providing information on nutrition.