In this article, we present a review on the topic of Learning Objects (LOs) based on case studies presented in the bibliography. We start by considering the origins of the term, various conceptualizations, and then focus on LO reutilization. The case studies selected are used to analyze aspects pertaining to LO creation and use in specific educational contexts. The results obtained can be used to consider issues such as reasons why educators choose to work with LOs, LO design methodologies (technological, pedagogical, hybrid), types of design scenarios (audiovisual, interactive, mixed), development tools (for assembling LO, generating contents, generating activities/self-evaluations, loading meta-data), publication environments (LO repositories and Virtual Teaching and Learning Environments), and assessment processes (tests with students and educators). This review reveals a positive, progressing outlook as regards LO creation and their incorporation/use in educational contexts. There are also some aspects that would have to be considered in more detail in relation to LO reutilization that are good for analysis and coming up with new lines of action.