The victim was part of a group of girls who were walking along Wallisdean Avenue, Fareham, between 8am and 8.30am on Friday when they were approached.
The man, who was unknown to them, began to make inappropriate comments and grabbed one of the girls.
The girl was not injured.
A 53-year-old man from Fareham has been arrested in connection with this incident and remains in custody, according to a spokesman from Hampshire Constabulary.
Detective Inspector Dal Andrews said: ‘Incidents of this nature are rare but we understand this will be upsetting for the local community.
‘Please be reassured that officers have been making enquiries in the area and have arrested a man. We have also been working with the school the girls attend to ensure all pupils are safeguarded and supported.
‘Police and partners regularly work with local schools to provide resources and advice around outdoor safety for children.
‘We have not received any other reports of incidents of this nature happening in the area, but if you have any concerns, or any information about the incident in question, please do not hesitate to contact us on 101 quoting 44210239141, or speak to the safeguarding officer at school if you are a parent.’
Police are advising concerned parents to access online resources at clevernevergoes.org to help keep their children safe when out in public.