Aspects relate to automatically establishing neighbor relations for adjacent sectors based on one or more network events. The neighbor relations can be established between sectors that can be identified as inter-frequency neighbors or intra-frequency neighbors. In an aspect, the network events can be active call data events received from one or more mobile devices. The active call data events can be radio access bearer establishments and internal system releases. In another aspect, the network events can be idle call data events received from one or more mobile devices. If a first event ended on a first sector and a second event started on a second sector before expiration of an interval that started when the first event ended, the first sector and second sector can be defined as neighbors.