Wild edible plants, and particularly weeds, continue to be an important dietary component of many people around the world. We study the availability and yield of 15 weedy vegetables traditionally consumed in the Mediterranean region to assess their potential sustainable exploitation. Fieldwork was conducted in Central Spain during 2007–2009. Yields ranged between 10–460 g per plant in non-clonal species and between 400–5,000 g m⁻² in clonal species. According to local plant density estimates, a total of 1800 kg ha⁻¹ for Foeniculum vulgare, 700–1000 kg ha⁻¹ for Beta maritima, Rumex pulcher, Papaver rhoeas and Silybum marianum, and 80–400 kg ha⁻¹ for the remaining species could be obtained, except for Scolymus hispanicus that only yielded 30 kg ha⁻¹. Exploitation of those species should consider local yields and preferences to achieve sustainability. We propose: 1) organic cultivation for highly valued species with low production rates in the wild (e.g., Scolymus hispanicus and Silene vulgaris); 2) commercial wild collection for culturally appreciated species with high yields in the wild (e.g., Allium ampeloprasum and Chondrilla juncea); and 3) maintenance of traditional practices and rates of harvest for all species for self-consumption.