The 24 year-old, who will wear the number 19 shirt at Arsenal, has signed from Ligue 1 side Lille where he scored 23 goals and made 12 assists in all competitions last season.
With the signing, Unai Emery adds even more firepower to his Gunners squad, with Pepe set to link up with Pierre-Emerick Aubameyang and Alexandre Lacazette to form a fearsome front three.
“Nicolas is a highly-rated and talented winger who was wanted by many of the top teams in Europe,” said Emery.
“Signing a top-class winger has been one of our key objectives in this transfer window and I’m delighted he’s joining. He will add pace, power and creativity, with the aim of bringing more goals to our team.”
Pepe said it will be an honour to play for Arsenal, and especially alongside the likes of Aubameyang and Lacazette – having played against the Frenchman when he was at Lyon.
“Being here is very emotional because it has not been easy for me. I have come a long way and struggled a lot and so signing for this great club is a big reward,” Pepe told Arsenal.com.
“When I knew I was coming to Arsenal, I immediately thought of the French guys who play here.
“I thought of Ozil, the world champions, Lacazette, Aubameyang and many more. Of course, these are the players who sprang to mind because I used to watch them when I was at Lille.
“Also, Lacazette used to play for Lyon and so I have had the opportunity to play against him. It will be an honour to play alongside him.”
Pepe said that advice from compatriot Kolo Toure helped to make up his mind about making the move to the Emirates.
“Kolo Toure was with us on the [Ivory Coast national] squad as an assistant coach [at the Africa Cup of Nations],” Pepe added.
“He spoke to me a lot about the very high level, how he got to Arsenal and how you always have to work hard and really graft on a daily basis to try and get right to the very top.
“Toure, Eboue and Gervinho are the major players from the Ivory Coast.
“We talk a lot about Gervinho, for example, who played for Lille and ended up at Arsenal, so I am on the same path. They are definitely examples to us young Ivorians and I hope we will continue to follow these examples.”