Resumen: We offer in this review a description of the vacuum energy of self-similar systems. We describe two views of setting self-similar structures and point out the main differences. A review of the authors’ work on the subject is presented, where they treat the self-similar system as a many-object problem embedded in a regular smooth manifold. Focused on Dirichlet boundary conditions, we report a systematic way of calculating the Casimir energy of self-similar bodies where the knowledge of the quantum vacuum energy of the single building block element is assumed and in fact already known. A fundamental property that allows us to proceed with our method is the dependence of the energy on a geometrical parameter that makes it possible to establish the scaling property of self-similar systems. Several examples are given. We also describe the situation, shown by other authors, where the embedded space is a fractal space itself, having fractal dimension. A fractal space does not hold properties that are rather common in regular spaces like the tangent space. We refer to other authors who explain how some self-similar configurations “do not have any smooth structures and one cannot define differential operators on them directly”. This gives rise to important differences in the behavior of the vacuum. Idioma: Inglés DOI: 10.3390/universe7050128 Año: 2021 Publicado en: Universe 7, 5 (2021), 128 [21 pp.] ISSN: 2218-1997 Factor impacto JCR: 2.813 (2021) Categ. JCR: ASTRONOMY & ASTROPHYSICS rank: 32 / 69 = 0.464 (2021) - Q2 - T2 Categ. JCR: PHYSICS, PARTICLES & FIELDS rank: 16 / 29 = 0.552 (2021) - Q3 - T2 Factor impacto CITESCORE: 3.2 - Physics and Astronomy (Q2)