Elneny has become a key member of Hector Cuper's squad that returned to the World Cup for the first time since 1990.
At club level, the former Basel player who plays several roles in the defence and midfield has made 26 appearances, scoring once and assisting twice in all competitions this season.
Mido had previously criticised Elneny for not being good enough for the top level.
However, with his recent performances, the former Middlesbrough forward took to social media to applaud the 25-year-old who extended his stay with the Gunners earlier this week.
“I followed the last three games of Arsenal and the last two team games from the stadium, and I have to admit that I was wrong about Elneny,” Mido tweeted.
“I am impressed by the level he has been playing in the recent period where he became an indispensable player in the Egyptian team. Congratulations to our player on renewing his contract with Arsenal.”
Elneny who won Arsenal's Player of the month for January could make his 10th league appearance of the season when Arsene Wenger's side host Stoke City at the Emirates Stadium on Sunday.