SummaryThe proximate composition, selected amino acid composition, and chemical constituents of Spirogyra neglecta (Hassall) Kützing, a freshwater algae collected from Phrae province, Thailand was investigated. It was found to be a good source of protein (29.42% dry wt. basis) and fibre (6.70% dry wt. basis). The total amino acid content was 2611.85 mg/100 g edible. The chemical constituents were characterised by GC–MS, which demonstrated that it contained phytol (62.10%), ethyl 5,8,11,14,17‐icosapentaenoate (8.55%) among others. Based on its chemical composition results, it could serve as a potential ingredient with high nutritional values in the food and nutraceutical industry. Furthermore, the descriptive sensory profile consisting of 17 descriptors, namely, green colour, glossy, filamentous, aroma (algae, grassy, fishy, and earthy), flavour (algae, grassy, fishy, and earthy), sweet, bitter, and texture (fibrousness and softness), mouthfeel (entire mouth‐coating), and aftertaste (astringent), were successfully developed to allow characterisation of the sensory quality of this algae.