They were sentenced to between two and five years in prison and fined for "involuntary homicide" and "breaching urban planning codes".
Three others were acquitted after the four-month trial, which prompted protests both from victims' families and the accused who charged that the "real culprits" were not in the dock.
In July 2014, 23 people died when the three buildings collapsed before dawn in Morocco's commercial capital, one of the worst disasters of its kind in the north African kingdom.