Osmolyte accumulation (OA) is often proposed as a key mechanism for increasing crop yields under drought conditions. The hypothesis is that OA helps maintain cell and tissue activity under water-deficit conditions by reducing cell osmotic potential, thus maintaining water absorption and turgor pressure. However, field studies have shown no consistent benefit of OA on crop yield. Positive associations were found under severe water deficits or special water-supply scenarios where much of the benefit is plant survival. Under conditions where water deficits threaten crop survival, yields are so low that even large fractional yield gains offer little practical benefit. The maintenance of turgor in cells is likely to result in crop behavior that is opposite to what is beneficial. The only clear mechanism identified for beneficial yield responses to OA is the maintenance of root development to access deeper soil water. OA is often associated with osmotic adjustment or osmoregulation, which is a selection criterion in traditional crop breeding to improve grain yield in dry environments. Research on OA has increased significantly in the last 20 years, with many publications. However, the explosion of investigations on OA has occurred with little evidence that crop yield is actually benefited by OA. The review highlights that most studies show no effect or even negative effects of OA on crop yield. The osmoprotection mechanism, which involves the accumulation of non-toxic compounds to protect cells, is not clearly differentiated from osmotic adjustment. The maintenance of cell and tissue water content and turgor is another hypothesis, but it may lead to continued growth and water use that is not beneficial under drought conditions. The maintenance of turgor may delay water-conserving mechanisms, leading to increased plant dehydration. The osmotic adjustment hypothesis is also discussed in terms of its potential to improve soil water recovery, but the results show that it is not effective in most cases. The review concludes that the only clear advantage of OA is in root tips, where osmolyte accumulation can allow continued root development into deeper soil, providing access to more water. Therefore, future research should focus on roots and root tips to improve crop performance under drought conditions.Osmolyte accumulation (OA) is often proposed as a key mechanism for increasing crop yields under drought conditions. The hypothesis is that OA helps maintain cell and tissue activity under water-deficit conditions by reducing cell osmotic potential, thus maintaining water absorption and turgor pressure. However, field studies have shown no consistent benefit of OA on crop yield. Positive associations were found under severe water deficits or special water-supply scenarios where much of the benefit is plant survival. Under conditions where water deficits threaten crop survival, yields are so low that even large fractional yield gains offer little practical benefit. The maintenance of turgor in cells is likely to result in crop behavior that is opposite to what is beneficial. The only clear mechanism identified for beneficial yield responses to OA is the maintenance of root development to access deeper soil water. OA is often associated with osmotic adjustment or osmoregulation, which is a selection criterion in traditional crop breeding to improve grain yield in dry environments. Research on OA has increased significantly in the last 20 years, with many publications. However, the explosion of investigations on OA has occurred with little evidence that crop yield is actually benefited by OA. The review highlights that most studies show no effect or even negative effects of OA on crop yield. The osmoprotection mechanism, which involves the accumulation of non-toxic compounds to protect cells, is not clearly differentiated from osmotic adjustment. The maintenance of cell and tissue water content and turgor is another hypothesis, but it may lead to continued growth and water use that is not beneficial under drought conditions. The maintenance of turgor may delay water-conserving mechanisms, leading to increased plant dehydration. The osmotic adjustment hypothesis is also discussed in terms of its potential to improve soil water recovery, but the results show that it is not effective in most cases. The review concludes that the only clear advantage of OA is in root tips, where osmolyte accumulation can allow continued root development into deeper soil, providing access to more water. Therefore, future research should focus on roots and root tips to improve crop performance under drought conditions.