This study aimed to investigate the interactions between ants and aphids on host plants in different habitats located in the northwestern part of Turkey. A total of 26 ant species belonging to 13 genera and 3 subfamilies from the family Formicidae (Hymenoptera) were found associated with 52 aphid species belonging to 22 genera from the family Aphididae (Hemiptera: Aphidoidea) on 66 host plant species from 24 plant families. In total, 132 tritrophic ants–aphids–host plants interactions including new associations were revealed. Also, we present results on the interactions of ants–aphids–host plants in different habitats such as cultivated, uncultivated and urban areas. About 85 tritrophic interactions of ants–aphids–host plants were revealed in cultivated, 27 tritrophic interactions in uncultivated and 20 tritrophic interactions in urban areas. Tritrophic interactions were more diverse in cultivated areas than uncultivated and urban areas. Our results reveal that the interactions between ants and aphids are highly diverse and that they vary on host plants in different habitats. It may be thought that this is due to the specialization resulting from the high diversity of host plants of aphids in cultivated areas and increased the presence of ants.