The growing use of experimental animals in biomedical research and education has intensified ethical, scientific, and economic concerns. Millions of animals are used in laboratories worldwide each year, and animal experimentation raises unavoidable moral questions while also requiring skilled personnel, specialised housing, and substantial financial investment. The Three Rs framework — Replacement, Reduction, and Refinement, first articulated by Russell and Burch (1959) — provides a structured strategy for minimising animal use without compromising scientific quality. This review surveys the principal categories of non-animal and reduced-animal alternatives currently available, including in vitro cell- and tissue-based systems, in silico and computational models, organ-on-a-chip microphysiological systems, donated human tissue, human patient simulators, non-invasive human imaging techniques, and invertebrate model organisms. For each category we summarise the underlying technology, its demonstrated applications, and its comparative performance against traditional animal tests where data are available. We also examine the practical, regulatory, and scientific limitations that currently constrain wider adoption of these alternatives. We conclude that no single alternative method can yet fully replace animal models across all research contexts, but that the coordinated use of multiple complementary approaches can substantially reduce reliance on animal experimentation while improving the human relevance of research and educational outcomes.