The chemical composition of the lipophilic and phenolic extractives of the leaves, stems and roots of the salt marsh plant Halimione portulacoides from the Aveiro Lagoon was thoroughly investigated by gas chromatography–mass spectrometry (GC–MS) and ultra-high-performance liquid chromatography–mass spectrometry (UHPLC–MS), respectively. The lipophilic fraction of leaves and stems is mainly composed of long chain aliphatic acids and alcohols (both in the C16–C30 range) and smaller amounts of sterols, such as schottenol, β-sitosterol and β-sitostanol. The major component of roots extract is a triterpenic ketone, hop-17(21)-en-3-one, accounting for 2.8 g kg−1 of dry material. Furthermore, thirteen phenolic compounds were firstly reported as constituents of this halophytic shrub. Among the studied plant tissues, leaves are the richest in phenolic compounds with 4.6 g kg−1 of dry material, most of which correspond to sulfated flavonoids (3.1 g kg−1 of dry material), particularly derivatives of isorhamnetin-sulfate.