Silky bentgrass (Apera spica-venti L.) is one of Central Europe’s most troublesome monocotyledonous weeds of winter crops. This study aimed to analyze the competitiveness of biotypes of silky bentgrass against winter wheat, depending on the type of soil substrate and nitrogen fertilization. In this research, in a pot experiment during two seasons, the effect of bentgrass plants, of different sensitivity/resistance to herbicides, on winter wheat was studied in an additive model. It was carried out on sandy or clay soil, either non-fertilized or fertilized with nitrogen. The competitive indices were calculated based on several wheat morphological and yield features. Multivariate analysis was incorporated to interpret the data. As a result, it was found that wheat performance was affected by bentgrass competition. No clear effect of soil type and nitrogen fertilization on the competitiveness of A. spica-venti biotypes was demonstrated. Only in one season was the pyroxsulam-resistant biotype competitive to the winter wheat when grown on fertilized clay soil. Further research with varied numbers of winter wheat and bentgrass is advised to assess crop-weed effects further.