Through cecidogenesis, a diverse array of secondary metabolites is produced, often different qualitatively or quantitatively from non-galled plant tissues. These compounds can be recognized as part of the battery of products released by plant biosynthetic machinery in response to injury, pathogens and endophagous herbivores. Alternatively, induced metabolites can be manipulated by the gall inducer organisms, their associates (e.g., microorganisms), or a combination of both. Plant volatile organic compounds (VOCs) have been recognized as mediators in plant-animal interactions; this also applies to the symbiotic relationship between plants and cecidogenic arthropods, which can use plant VOCs for host location and foraging, among others. Besides, plant VOCs may change due to gall development, corresponding to herbivore-induced plant VOCs (HIPVs). Depending on the ecological context, these may work as indirect plant defenses, modifying plant VOCs after cecidogenesis and attracting gall-inducer’s natural enemies, such as parasitoids and predators. Otherwise, gall-related plants’ VOC changes may make them less detectable to these gall-inducer enemies or even be used as an inducible proxy for mating pheromones, benefiting the inducer in the process. Besides gall inducers and their predators and parasitoids, galls constitute a crucial resource for other associated animals such as inquilines, successors, and gall herbivores. However, the semiochemical value of plant VOCs for these associates has been less explored. For example, plant-modified VOCs may help gall-inducing insects deter gall herbivores that can consume the gall and their gall-inducers. We discuss the need to integrate current knowledge of the gall-associated community and plant semiochemical signals to fathom the relevance of novel chemical phenotypes emerging along with gall development.