The Rams hired Chelsea legend Frank Lampard as boss earlier this summer and the aforementioned pair have joined the club as his first signings.
Mason, a midfielder, spent last season on loan at Vitesse Arnhem and registered 14 goals along with nine assists. Wilson, meanwhile, plays as a winger and scored seven goals in 13 appearances on loan at Hull City last season.
"Derby County have completed deals to bring exciting attacking duo Mason Mount and Harry Wilson to Pride Park Stadium on season-long loan deals," the club announced via their official website on Tuesday.
"The pair join from Chelsea and Liverpool respectively and become Frank Lampard’s first signings since he was confirmed as the Rams’ boss, enhancing his options in the final third ahead of the 2018/19 Sky Bet Championship campaign."
“I’m delighted to get both of these deals done and add players of their quality and calibre to the squad," Lampard added. “I know Mason really well from my Chelsea links and I have also watched him play in their very successful youth teams.
“I knew him from those days and I watched him closely at Vitesse, where he took it by storm.
“Harry brings incredible quality and hunger to the table here and he showed that last year while he was on loan at Hull. He’s a full international too and he has a real desire to come here and improve."