Crop productivity is negatively affected by various environmental stresses such as cold, heat, drought, salinity and heavy metal stress. Plants, due to their sessile nature, have thus developed various mechanisms to adapt themselves under abiotic stress conditions. Epigenetic mechanisms play a pivotal role in plant stress adaptations by inducing alterations in gene expression without modifying the DNA sequence. Epigenetic modifications are reversible and confer a dynamic plasticity to the plant’s molecular mechanisms, thereby enhancing their growth, survival and adaptability via modulating gene expression in response to abiotic stressors. Epigenetic mechanisms include DNA methylation, histone modifications and non-coding RNA-mediated regulations. In this book chapter, we are elaborating these fundamental but essential epigenetic mechanisms in crop plants under optimal as well as common abiotic stress conditions, including heat, drought, salt and cold. We are also investigating some cereal crop studies to highlight epigenetic markers associated with agriculturally important traits. These markers can further help the researchers develop abiotic stress-resilient crop varieties. Finally, we are highlighting the concept of stress memory and its agricultural implications, which can help researchers develop abiotic stress-resilient crop varieties.