This came up a little while back, and while the response only covers the US, and can probably be expanded upon further if someone comes along, /u/amescg does a pretty good job providing some overview of the copyright in the US here.
This is actually a very timely question.
The Free State, as the legal inheritor of the rights of the Franz-Eher-Verlag (the original publisher of the work), owned the German copyright to Mein Kampf. So no version of the work could be printed in Germany without the express permission of the Bavarian government, which the Free State steadfastly refused to give. But, as it would happen, German copyright law lasts for only 70 years after the death of the author, and wouldn't you know it, Hitler died in 1945, so 2016 marks 70 years after his death. As it would happen, the Institut für Zeitgeschichte (Institute of Contemporary History) in Munich has plans to publish a critical edition of the pesudo-biography propaganda work with some 5000 pieces of commentary. Folks who have an English language copy will know the work is about 750 pages, give or take, but this new critical edition is expected to run some 2000 pages, which suggests that the critical commentaries will take up more words than the original tract itself.
Also of interest, I suspect, is the fact that in 2014, the Justice Ministers of the various German states got together, recognizing that the copyright was running out, and wondered what they were going to do about this. They decided that further printings of the regular version (i.e. not a critical edition with historical commentary, but just the tract itself) would remain forbidden, and that they would prosecute any such publications under Germany's already extant law against "incitement of the masses" (Volksverhetzung).