Spontaneous lavender growing in uncultivated fields in Portugal have been used in traditional medicine for internal and external uses. The essential oils (EOs) of Lavandula stoechas subsp. luisieri are characterized by the presence of trans-α-necrodyl acetate and trans-necrodol. These EOs are able to prevent the generation and deposition of neurotoxic β-amyloid peptide in Alzheimer’s disease. The EOs also present antibacterial, anti-fungal, anti-Leishmania, antioxidant, anti-inflammatory and antifeedant effects. In the case of hydrodistillation, the predominant compound of Lavandula viridis EO was 1,8-cineole, nevertheless in the case of supercritical fluid extraction, the main constituent was camphor. In in vitro shoots EOs, 1,8-cineole and α-pinene were the most important compounds. The EOs presented anti-fungal activity particularly against Cryptococcus neoformans and dermatophytes. The antioxidant and anti-protozoal activities of L. viridis EOs were lower than L. stoechas subsp. luisieri EOs, with hydrodistillation being the best method for obtaining samples with higher antioxidant and anti-acetylcholinesterase activities. The presence of fenchone, 1,8-cineole and camphor was a common trace of the Lavandula pedunculata subsp. pedunculata EOs and in in vitro axillary shoots EOs. Lavandula pedunculata subsp. lusitanica EOs were predominantly constituted of fenchone and camphor. The antioxidant activity of L. pedunculata subsp. lusitanica EOs was poorer than other Lavandula EOs from Portugal.