Several studies have been carried out regarding secondary school student's abilities in classifying plants in Latin-based countries, but never in the Arabic world. The aim of the current study is to measure Moroccan secondary high school students' abilities in classifying plants. The data were collected by administering a task individually to 230 Moroccan secondary school students aged between 14-16. The students were asked in the written task to determine the class of five plants and to give some commons names of gymnosperms and angiosperms classes. We provided students with an identification key in order to help them. The data was performed from a quantitative perspective in order to detect statistically significant about Moroccan students' abilities in classifying plants. We found that Moroccan secondary school students have poor botanical classification knowledge and serious problems towards botanical identification and recognition of species' morphological characters. Therefore, we conclude that they had difficulties to distinguish between gymnosperms and angiosperms plants and also between mosses and the ferns.