The game will kick off in the Dutch capital at 7.15pm.
Due to Covid-19 restrictions, no away supporters will be permitted to attend the friendly with Ajax and no tickets for the fixture will be made available.
Meanwhile, United have also revealed that they will face La Liga outfit Real Betis in a pre-season friendly to be staged at Loughborough University on Saturday, July 31.
The game will kick off at 12.30pm.
Ajax's first-team squad includes a number of players who were in the Netherlands' Euro 2020 squad including Steven Berghuis, Jurrien Timber, Maarten Stekelenburg and Ryan Gravenberch.
Betis' star turns include French international Nabil Fekir, Spanish forward Borja Iglesias and Portuguese midfielder William Carvalho.
Both games will be streamed live with further information to be screened next week.
Leeds start their pre-season with their annual trip to Nethermoor to face Guiseley.
The fixture takes place on Tuesday, July 27 (7.30pm), with Marcelo Bielsa's side visiting Blackburn Rovers on the following evening, Wednesday, July 28 (7.30pm).
On Friday, July 30, Leeds also make another trip to Lancashire to face Fleetwood Town - managed by ex-United boss Simon Grayson - with the game kicking off at 7pm.