Saudi Arabia is ordering its citizens to leave Canada, selling its financial assets there and freezing trade between the two countries as part of an extraordinary diplomatic spat that has brought into global view the kingdom’s extreme sensitivity to Western criticism.

The steps follow the Canada’s foreign ministry’s chastising Saudi Arabia for its recent arrest of human-rights activists. Canada’s foreign ministry, in a Twitter message sent on Friday, called on Saudi authorities to “immediately release” the activists.

The...