The biodiversity of Apis mellifera intermissa in the northern parts of Algeria is analysed using geometric morphometric investigations of workers' forewing variability. A total of 3400 worker bees was collected from hived colonies throughout the northern parts of Algeria, between 35°19′N–37°01′N and 00°54′W–8°06′E. Results showed a clear differentiation between the main three northern ecological regions. Differences involve mostly shape, while size contribution is generally weak. Within regions, shape variability between apiaries and colonies does not appear related either to the geographic location or to altitude. The large variability observed at the colony and apiary levels can possibly be related to anthropogenic introductions or exchanges, and it is concluded that both drift and polyandry are the most probable explanations. Finally, phenotypic differences between ecological regions probably result from restrictions to gene flow between their respective populations. Nevertheless, the relative contributions of local adaptations to environmental factors and to beekeeping remain to be established.