The coordination between the endoplasmic reticulum (ER) and mitochondria is increasingly recognized as a central regulator of skeletal muscle metabolism and, consequently, meat quality. Here, we summarize recent progress on how ER–mitochondrial communication regulates muscle metabolism and meat-quality traits. This interaction, primarily mediated by mitochondria-associated membranes, integrates key cellular processes, including calcium signaling, redox homeostasis, lipid metabolism, and cellular stress responses. These events then lead to tissue-level outcomes such as intramuscular fat deposition, transitions in muscle fiber types, and postmortem apoptotic or proteolytic events, all of which influence meat quality. However, comparative studies across livestock species reveal notable gaps and inconsistencies, highlighting the need for deeper mechanistic investigation. Overall, deepening our understanding of ER–mitochondria crosstalk will inform nutritional or molecular strategies to enhance meat quality and clarify species-specific regulatory mechanisms.