In 2008, the first movie of what we now call the Marvel Cinematic Universe was released. At that point, with just Iron Man, the timeline was easy to understand: 2010. But then, they started making Captain America movies that were set in the 40s, during the world war and Avengers movies where everyone came together and their narratives had to blend. As they tried to keep up with all the weaving threads of the series, they eventually ran into some problems, like the moment in Spiderman: Homecoming that put the movie eight years after the first Avengers, which would be the year 2020, much later the Infinity War. As Kevin Feige put it:

All of that debate has made us go, 'Okay, at some point, I'm not sure exactly when, we're going to publish a timeline and see what it all is.' It wasn't meant to flummox anybody exactly, and I'm not sure I'd do it again the same way, but it does all connect to where we placed it. Other than very particular instances where there's a newspaper, or verbal reference to years, we never date the films.

Here's the official timeline below, as compiled by Screen Rant:

  • 1943-1945: Captain America: The First Avenger
  • 2010: Iron Man
  • 2011: Iron Man 2The Incredible HulkThor
  • 2012: The AvengersIron Man 3
  • 2013: Thor: The Dark World
  • 2014: Captain America: The Winter SoldierGuardians of the GalaxyGuardians of the Galaxy Vol. 2
  • 2015: Avengers: Age of UltronAnt-Man
  • 2016: Captain America: Civil WarSpider-Man: Homecoming
  • 2016 through to 2017: Doctor Strange
  • 2017: Black PantherThor: RagnarokAvengers: Infinity War