West Yorkshire Police is treating the incident “extremely seriously” after receiving a report from the mother of the teenager.
She said her 14-year-old daughter was walking on Nab Croft Lane in Huddersfield at around 4.15pm on Monday when a man in a car approached to ask for directions.
He then reportedly indecently exposed himself before driving off.
The teenage girl was left unharmed but understandably very shaken, the force added.
The man is described as Asian, in his mid 20s, with dark brown, curly hair and goatee beard.
He reportedly spoke with a Huddersfield accent and was driving a bright blue sporty vehicle.
Police have increased their patrols in the area and are urging any witnesses to come forward.
Police appeal for dash cam footage
“We are treating this incident extremely seriously and are carrying out extensive enquiries to trace the man involved,” said Detective Inspector Will Denton at Kirklees Safeguarding.
“I would appeal to anyone who was in that area at that time who may have seen the incident or who saw a man matching that description to come forward.
“I would also appeal for any dashcam footage from vehicles driving in the area at that time,” added DI Denton.
“This was distressing for the young girl involved and will obviously cause concern in the local community.
“Our local neighbourhood policing team have increased their patrols and will be working in the community to provide reassurance.”
Anyone with information is asked to contact police via 101 or use the live chat options at www.westyorkshire.police.uk/livechat quoting crime reference 13260066752