The Kia Stonic is structurally identical to the Kia Rio, assessed by Euro NCAP in September 2017, and shares the same safety equipment and interior trim.  This rating for the Stonic is based on tests performed on the Rio and additional data reviewed by Euro NCAP.

The passenger compartment remained stable in the frontal offset test.  There was insufficient pressure in the driver's airbag to prevent the head from 'bottoming out' the airbag.  Protection of the head was downgraded to adequate as a result.  Dummy readings indicated good protection of the knees and femurs of both the driver and passenger.  Kia showed that a similar level of protection would be provided to occupants of different sizes and to those sat in different positions.  In the full-width rigid barrier test, protection of critical body areas was good or adequate for the driver and rear passenger.    In the side barrier test and in the more severe side pole impact, protection of all critical parts of the body was good and the car scored maximum points in these tests.  Tests on the front seats and head restraints demonstrated good protection against whiplash injuries in the event of a rear-end collision while a geometric assessment of the rear seats indicated marginal whiplash protection.  The car has, as part of its optional safety pack, an autonomous emergency braking system but the results of those tests are not included in this rating.

In the frontal offset test, protection of the chest of the 6 year dummy was rated as marginal, based on dummy readings of chest decelerations. Otherwise, protection of the 6 and 10 year dummies was good or adequate.  In the side barrier test, protection of both dummies was good.  The front passenger airbag can be disabled to allow a rearward-facing child restraint to be used in that seating position.  Clear information is provided to the driver regarding the status of the airbag and the system was rewarded. All of the restraint types for which the car is designed could be properly installed and accommodated in the car with the exception of the Group II/III universal restraint which was unstable in the rear centre position.

The bonnet provided predominantly good or adequate protection to the head of a struck pedestrian, with some poor results recorded on the stiff windscreen pillars.  The bumper provided good protection to pedestrians' legs at all test locations and the pelvis was also well protected, the car scoring maximum points in these tests.  The optional autonomous emergency braking system can detect pedestrians but the results are not included in this assessment of standard safety equipment.

A seatbelt reminder system is standard equipment for the front and rear seats.  Autonomous emergency braking and a lane assistance systems are part of the optional safety pack, the results of which are not included in this rating.