Polyamines are small molecules that play regulatory roles in plant responses to abiotic stress. Recent studies have revealed their key functions in regulating abiotic stress tolerance through genetic, transcriptomic, and metabolomic approaches. However, the precise molecular mechanisms by which polyamines control plant stress responses remain largely unknown. Polyamine signaling is involved in direct interactions with metabolic pathways and hormonal cross-talks. This review discusses the integration of polyamines with other metabolic pathways, focusing on their molecular mechanisms in abiotic stress tolerance. Recent advances in the cross-talk between polyamines and abscisic acid (ABA) are discussed, integrating processes such as reactive oxygen species (ROS) signaling, nitric oxide generation, ion channel modulation, and Ca²+ homeostasis. Polyamines are nitrogen-containing compounds of low molecular weight, found in all living cells. While polyamine biosynthesis in plants may have originated from an ancestral cyanobacterial precursor, it is an ancient metabolic route present in all organisms. Polyamines are essential for life, and their depletion is lethal in yeast, protists, and plants. Although spermine (Spm) is not essential, it plays important roles in growth and development. Initially, polyamines were thought to have structural roles due to their ability to bind anionic macromolecules. However, they also act as regulatory molecules in many fundamental cellular processes, including cell division, differentiation, proliferation, cell death, DNA and protein synthesis, and gene expression. In plants, polyamines are involved in various physiological processes, including organogenesis, embryogenesis, floral initiation, leaf senescence, fruit development, and abiotic and biotic stress responses. Changes in polyamine metabolism occur in response to abiotic stresses, with putrescine (Put) accounting for a significant portion of the nitrogen in stressed plants. The sequencing of the Arabidopsis genome has facilitated the use of global 'omic' approaches to identify target genes in polyamine biosynthesis and signaling pathways. Loss and gain of function mutations provide insights into polyamine functions. Recent studies suggest that polyamines may act as cellular signals in cross-talk with hormonal pathways, including ABA regulation of abiotic stress responses. However, the transfer of this technology to valuable crops has current constraints in the agricultural industry. Further exploration of natural variability may open new alternatives for both fundamental and applied plant polyamine research.Polyamines are small molecules that play regulatory roles in plant responses to abiotic stress. Recent studies have revealed their key functions in regulating abiotic stress tolerance through genetic, transcriptomic, and metabolomic approaches. However, the precise molecular mechanisms by which polyamines control plant stress responses remain largely unknown. Polyamine signaling is involved in direct interactions with metabolic pathways and hormonal cross-talks. This review discusses the integration of polyamines with other metabolic pathways, focusing on their molecular mechanisms in abiotic stress tolerance. Recent advances in the cross-talk between polyamines and abscisic acid (ABA) are discussed, integrating processes such as reactive oxygen species (ROS) signaling, nitric oxide generation, ion channel modulation, and Ca²+ homeostasis. Polyamines are nitrogen-containing compounds of low molecular weight, found in all living cells. While polyamine biosynthesis in plants may have originated from an ancestral cyanobacterial precursor, it is an ancient metabolic route present in all organisms. Polyamines are essential for life, and their depletion is lethal in yeast, protists, and plants. Although spermine (Spm) is not essential, it plays important roles in growth and development. Initially, polyamines were thought to have structural roles due to their ability to bind anionic macromolecules. However, they also act as regulatory molecules in many fundamental cellular processes, including cell division, differentiation, proliferation, cell death, DNA and protein synthesis, and gene expression. In plants, polyamines are involved in various physiological processes, including organogenesis, embryogenesis, floral initiation, leaf senescence, fruit development, and abiotic and biotic stress responses. Changes in polyamine metabolism occur in response to abiotic stresses, with putrescine (Put) accounting for a significant portion of the nitrogen in stressed plants. The sequencing of the Arabidopsis genome has facilitated the use of global 'omic' approaches to identify target genes in polyamine biosynthesis and signaling pathways. Loss and gain of function mutations provide insights into polyamine functions. Recent studies suggest that polyamines may act as cellular signals in cross-talk with hormonal pathways, including ABA regulation of abiotic stress responses. However, the transfer of this technology to valuable crops has current constraints in the agricultural industry. Further exploration of natural variability may open new alternatives for both fundamental and applied plant polyamine research.