The pair triumphed over other contestants, Whitney Adebayo & Lochan Nowacki, Ella Thomas & Tyrique Hyde and Molly Marsh & Zachariah Noble, who finished in second, third and fourth place respectively.
"I thought I was going to be here a couple of days, then in and out of the door," said Sammy after the result was announced, with Jess adding that she "couldn't believe it".
However, many were taken by surprise with the win as predictions were in favour of Whitney and Lochan. Many fans were left divided by the win - with some happy for them while others were left surprised how Whitney and Lochan - who took second place didn't take the crown.
"Nah but fr how did Jess and Sammy actually win? #loveIsland," one penned, whilst a second fan added: "I literally watched love island for Whitney how how how how how did Sammy and Jess win I was so invested #loveIsland."
Another tweeted: "Holy s*** did not expect Jess and Sammy to win #Loveisland! Delighted though Jess is unreal!"
Jess and Sammy have been mainstays on the Island throughout the series, with the former being the first contestant to enter the villa this year while Sammy subsequently joined on Day 4.
Despite testing the waters with other Islanders, Sammy realised his heart was set on Jess during Casa Amor, which saw him feel guilty after recoupling while she remained single.