Bioactive glasses play an important role for the bone defects treatment. Forty years ago, it was discovered the first bioactive glass, Bioglass®, obtained by melting and used in Orthopedics and Dentistry. Twenty years ago, another family of bioactive glasses obtained by solgel processing was reported. Solgel glasses exhibit high textural properties and quicker bioactive response than melt glasses. However, their presence in the market is scarce which could be explained considering that the improvements they bring do not justify the costs of their translation to product. In the last decade, so-called template glasses exhibiting greater bioactivity than solgel glasses were described. These glasses display high pore volume and ordered mesopore structure, which makes them optimal candidates for hosting biologically active substances. For these characteristics, template glasses are being considered ideal candidates for the scaffolds manufacture used in bone engineering. This article shows the main features of three families of bioactive glasses and the importance of their nanostructure in the bioactivity. We demonstrate here that glasses with identical composition may exhibit very different properties, specifically bioactivity, as a function of their nanostructure. This fact demonstrates the importance of controlling this nanostructure in the design of new bioactive materials for bone regeneration.