The short answer
Yes. Vegetable tagines, couscous with vegetables, lentil and chickpea soups, Moroccan salads, fresh bread and fruit are on most menus, and several Marrakech cafés are fully vegetarian. The catch is meat broth or a little meat in some classic dishes, so ask each time, and mention it when you book a food tour or cooking class.
In more detail
Moroccan cooking leans heavily on vegetables. A vegetable tagine is on almost every menu in the city. Cooked salads such as zaalouk, made from aubergine, and taktouka, made from peppers and tomato, come as a spread before the main course. Bread is fresh at every meal, and breakfast is msemen and baghrir with honey. Fruit is everywhere.
The traps are quiet ones. Couscous is traditionally steamed over a broth of meat and vegetables, so ask for a vegetable-only version. Harira, the tomato, lentil and chickpea soup, sometimes has a little meat in it. Ask the cook, and you will usually get a straight answer.
Several places make it easy. Ayaso Medina is a three-level vegetarian and vegan café overlooking the spice square. World Storytelling Cafe near the Ben Youssef Madrasa is fully plant-based. In Gueliz, Ayaso Gueliz runs a vegetarian organic menu and Bloom House serves an all-day vegetarian and vegan breakfast. Near Jemaa el-Fnaa, Cafe Chez Zaza and Cafe Medina Rouge both offer vegetarian versions of their tagines and classics.
The night stalls of Jemaa el-Fnaa are mostly grills and meat, but you can still eat well there on bread, salads and fried potato maakouda. Our evening food tour is partly vegetarian: tell us in advance and the guide steers the route towards meat-free stalls where possible.