Confectionery sunflower (Helianthus annuus L.) has been cultivated in Spain for many years in small vegetable gardens for self-consumption, and this has created a vast genetic diversity of local landraces. The objective of this research was to assess variation in seed quality traits in a germplasm collection of Spanish local landraces of confectionery sunflower. Seed weight, kernel percentage, oil content, fatty acid composition, squalene, tocopherol and phytosterol contents, and tocopherol and phytosterol composition, were analysed in 137 landraces grown for 2 years in Córdoba, Spain. The evaluation was hindered by large differences for flowering time between accessions (>90 days), which made it difficult to separate genetic from environmental effects. The collection contained large variability for all traits evaluated. Of particular relevance were the ranges of variation (2-year averages) for squalene content (12–128 mg kg^–1 seed kernel), tocopherol content (114–423 mg kg^–1 seed kernel) and Δ⁷-stigmastenol content (7.1–35.2% of total phytosterols). Some traits were associated with specific locations; for example, all seven accessions collected in Espiel (Córdoba province) had high Δ⁷-stigmastenol content, although they differed for other traits. Some of the accessions evaluated in this research are valuable genetic sources for breeding programs focusing on seed and oil quality in sunflower.