Does the order of playing the single player or co-op campaigns matter?

In terms of plot, player training and (most importantly!) any potential spoilers between the two "branches", does it matter in which order the single player and co-op campaigns in Portal 2 are played through?

Nope.

The two campaigns are independent of each other, with different characters, different 'storylines' (although the storyline in co-op doesn't show through so much) and different endings.

The only reason why the order of playing could matter is the timeline, as SP takes place before the MP.

But in terms of plot and potential spoilers it isn't a problem at all as Thomas mentioned. In player training however, you aren't shown how the new game elements work but only instructed. But this should still be fairly easy to experiment with the game elements and thus a new player should be able to still complete the MP with ease.

All MP characters are seen in SP; so, play SP later if you want to know where the robots come from...

There are a few references that suggest single player should be played before co-op.

1. Glados talks about "another couple" in the co-op game, and what happened to them.
2. In the single player, near the end, you actually get introduced to the co-op team as being a replacement for human testing.

So - chronologically and storyline wise, co-op should follow single player. In practice, it doesn't really matter as 99.999% of the story is not affected.

• Single-player is set before Multi-player but there aren't any spoilers.
• Single-player introduces you to all the techniques better so you may not know how to use some of the testing elements if you go straight into Multi-player.