Wikipedia’s Moroccan cuisine article describes lamb as the most commonly eaten meat in Morocco.
Lamb appears throughout Moroccan cooking, especially in tagines and couscous dishes. It is often simmered with vegetables, onions, preserved fruit, or aromatic spices such as cumin, ginger, cinnamon, and saffron. The meat’s prominence reflects both culinary tradition and the importance of sheep in Moroccan food culture.
Moroccan cuisine is broader than a single meat. Chicken is widely used in tagines and roasted dishes, while beef, goat, seafood, and preserved meats also have established places in the national diet. The famous tagine of lamb with prunes is a classic example of Morocco’s fondness for combining savory meat with sweet dried fruit.
A common mix-up comes from another description of Moroccan food that distinguishes between total meat consumption and red meat. Some references identify chicken as the most widely eaten meat, or beef as the leading red meat. However, the cited Moroccan cuisine article specifically names lamb as the most commonly eaten meat, making lamb the intended answer for this question.