This article deals with the parable about pulling up the tares in the Coptic Gospel of Thomas (log. 57). It interprets this parable in the literary and theological context of this gospel and compares it with its parallel in the Gospel according to Matthew. The tares/weeds can represent those who did not reach a true understanding of the Father's kingdom and so they could not enter it. In the Gospel of Thomas the phrase 'the day of the harvest' is not to be understood apocalyptically or eschatologically; it confirms and emphasizes the radical and definitive fate of those people without true knowledge and it also points to the essential relevance of the understanding of the kingdom already present in the world. Comparison with Matthew's parallel has shown that the author of GThom knew and took over the canonical version; modifying it, he placed emphasis on pulling up the tares/weeds.