Valve has never indicated that a new Portal game is about to be released or is being developed but the fans all seems to believe that there will be a Portal 3. In fact, some of them believe that the game is actually not that far away.
We know that Valve has a history of not being able to reach the third game for most of their popular franchise so most people have actually given up hope on Portal 3. The other believe that the third installment will eventually be released because the story has not been completed yet.
At the end of the second game, we saw Chell in a field with a companion cube. Some players think that Valve definitely had the intention to continue the story. There are other who also believe that Valve might combine both Portal 3 and Half Life 3 and release it as one game.
We honestly hope that that would happen but at this point, it does not look like Valve is interested in making single player games like this. Do you think Portal 3 is going to happen?