The study, part of UNICEF's report on child well-being, looked at cannabis consumption by teenagers in the 29 wealthiest countries in the word.
The UN body found Spanish adolescents to be the third biggest marijuana smokers in the developed world, behind only Canada and Switzerland in the rankings.
France and the US were closely behind Spain in the teenage weed smoking list.
“It’s true that in earlier studies Spain’s teenage population also showed a high rate of cannabis consumption,” UNICEF Child Policies officer Gabriel González Bueno said.
Bueno told news daily 20minutos the results were linked to cultural habits and a certain degree of “tolerance” towards soft drugs in Spain.
The findings are not as bad as they were ten years ago, though.
Although Spanish teens still smoke cannabis more often than most of their European counterparts, UNICEF’s results from 2001–2002 show a five percent drop in consumption in the last decade in Spain.
“It’s not as if we deserve a prize, but there are reasons to be happy,” said Ignacio Calderón, director of Spain’s drug addiction foundation FAD.
“Spain’s always ranked high in drug consumption. The drop in usage doesn't mean we’re OK, but at least figures for cannabis and other drugs are either stabilizing or dropping."
Calderón believes teenage binge drinking is a far bigger cause for concern than cannabis consumption, due to the sharp increase over the past few years.
Thirty-six percent of Spaniards between the ages of 14 and 18 admitted to drinking too much in the last month, according to a study by Spain's National Drugs Plan.
“That’s an 11 percent increase in four years, from 2006 to 2010,” Calderón warned.
“These shocking figures are proof of what habits young Spaniards are taking up.”