Former Crystal Palace youngster has agreed a deal with the Terriers and will become their first signing of the season subject to a medical
The 21-year-old becomes Simon Grayson's first signing of the summer as the Terriers look to bolster their squad to meet the demands of Championship football.
Scannell is a highly decorated youth footballer, appearing for the Republic of Ireland under-17, under-19 and under-21 teams, but he has also received senior international recognition in the form of a call-up from Giovanni Trapattoni in May 2008.
Terriers boss Simon Grayson is delighted to have captured the forward's signature and praised his adaptability and experience.
"He is an exciting, young, talented footballer who is very adaptable," Grayson told Huddersfield's official website. "He can play on either wing or just off the striker - he offers great options."
He continued: "Despite his young age he brings bags of experience at both Championship and international level and hopefully he will be able to fulfil his potential with us.
"It wasn't that long ago that a lot of top class clubs were taking a look at him so we are delighted to now have him amongst our ranks."