Cafodd y gwasanaethau brys eu galw i'r digwyddiad rhwng Gwesty Penygwryd a Chapel Curig am tua 07:00 fore Iau.
Bu farw'r bachgen ac mae dynes 18 oed hefyd wedi dioddef anafiadau difrifol yn y gwrthdrawiad.
Mae pedwar arall hefyd wedi'u cludo i Ysbyty Gwynedd ym Mangor gydag anafiadau llai difrifol.
Mae Heddlu Gogledd Cymru wedi apelio am dystion, ac yn awyddus i siarad ag unrhyw un welodd gar Renault Clio du yn teithio rhwng Beddgelert a Phenygwryd rhwng 06:30 a 07:00.

The think tank said the city's 1,536 schools needed to save £360m in the first year if the government's National Funding Formula (NFF) plan goes ahead.
The amount is the equivalent of 12,857 qualified teachers, on an average salary of £28,000.
The government said London was the highest funded part of the country.
It added that under the plans, which are under consultation, inner-city schools would be allocated 30% more money per pupil than the national average.
But London Councils, which represents the city's 32 boroughs and the City, said no school would gain enough funding from the NFF to compensate for increased cost pressures from inflation, higher pension contributions and national insurance.
Ministers said the new formula was needed to tackle uneven levels of funding across England, with the best funded areas getting more than £6,300 per pupil per year, while the worst-funded averaging £4,200.
It said the funding cut was on top of National Audit Office figures which showed England schools faced an eight per cent real-terms cut per pupil by 2019-20 because it  wider cost pressures.
In a statement, London Councils said: "At a time when UK schools are seen as underperforming by international standards, and when businesses based in London are facing massive uncertainty about recruiting skilled staff, there is an urgent need to invest in schools in London and across the rest of the country."
It added: "Without the right qualifications and skills, London's children will be unable to access jobs and contribute to the national economy. Over 60% of jobs in inner London require a degree and around 45% of jobs in the rest of the capital require a degree."

The attacker, who was caught assaulting the woman in Holloway, north London, was jailed for six years by Blackfriars Crown Court.
The case went ahead under the assumed name Aurilien Cheyroux, as the authorities could not confirm his true identity, other than him being French.
The judge ruled he should be deported once his sentence was served.
Passers-by saw "Cheyroux" partially-dressed and struggling with a woman on Caledonian Road in the early hours of 1 March, the court heard.
He ran off, but was caught by witnesses and held until police arrived.
The woman told the witnesses she was uninjured and left the scene before police arrived.
The attacker told police he was a French national and gave the name used in the trial.
But after taking finger prints the French authorities said the information was incorrect. They were unable to establish a true identity.
Det Const Kip Malek said: "This is a highly unusual case where we have been unable to trace the victim and the man who has been convicted is under an assumed name.
"Despite this we have been able to get a conviction and that is due to the brave members of the public who witnessed the attack and took it upon themselves to pursue this man and contact us."
Cheyroux was found guilty of attempted rape but had previously pleading guilty to sexual assault.
Det Insp Neil Smithson added: "I am still keen to ascertain his identity. Equally, if you were the victim of this offence please contact us."
Mae bachgen 17 oed wedi marw a dynes ifanc wedi'i hanafu'n ddifrifol yn dilyn gwrthdrawiad rhwng car a bws mini ar ffordd yr A4086 ger Capel Curig.
[NEXT_CONCEPT]
About 70% of London schools could face budget cuts under government plans to change how they are funded, according to London Councils.
[NEXT_CONCEPT]
A man has been jailed for attempted rape despite police not knowing who he is or finding his victim.