Psychology and justice interact to such an extent that a sub-discipline has emerged in Psychology, focusing on its contributions and applications to justice, rights, and the law. In Latin-based languages, this subdiscipline is known as "Juridical Psychology" (Psicología Jurídica). In English-language literature, it is referred to by various names and generally has a narrower scope, due to the lack of a direct equivalent for the term jurídica. The interaction between psychology and the law occurs on three distinct levels: Psychology of Law (Psicología del Derecho); Psychology in Law (Psicología en el Derecho); and Psychology for Law (Psicología para el Derecho). Psychology of Law aims to advise the legislator in the creation of laws, given that laws regulate human behavior. Psychology in Law aims to transfer scientific knowledge regarding the psychological factors involved in legal statutes and norms. Finally, in Psychology for Law, psychology serves an ancillary role to the law, such as in forensic psychology. All these levels share the common feature of contributing knowledge and techniques that must be based on scientific evidence, in accordance with legal and case law criteria. This monograph provides evidence for several applications within this framework: the assessment of suggestibility in the testimony of child witnesses; the validation of a technique for assessing temporary occupational disability due to psychological causes (Psychology for Law: forensic task); the validation of a technique for assessing self-deception in child custody disputes (Psychology for Law: forensic task); the validation of an instrument to measure the mental health needs of minors under therapeutic judicial measures (Psychology for Law: forensic task); and the characteristics of perpetrators and victims of cyber-control (Psychology of Law: counselling to lawmaker)