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Randy Quaid can't seem to get things right north of the border ... he was just detained in Canada and it could lead to his deportation.

Law enforcement tells TMZ Quaid was picked up in Montreal where he and his wife Evi live. It appears Evi was involved in the incident as well, she tweeted, "i love that Canada needs to learn how to wake up and criticize its crappy government ... ps we got arrested by an actual tall midget."

It's unclear why Quaid was detained but an immigration official tells TMZ he will have a detention review hearing on Thursday.

A law enforcement source in Santa Barbara -- where Quaid has several warrants out for his arrest -- tells TMZ they'll pick him up once he's brought back to the US.