No, this is a gluten grain
Wheat, despite sitting with the grains. Couscous is pasta — durum semolina rolled into pellets and steamed — so it is never gluten-free unless made from corn or sorghum and sold as a substitute.
Gluten-containing grain under 21 CFR 101.91.
Pasta, not a grain. Semolina — coarsely milled durum wheat — is moistened, rolled between the hands or by machine into tiny pellets, then steamed and dried. Moroccan couscous is the fine version; Israeli couscous, also sold as ptitim or pearl couscous, is the larger toasted one, and Sardinian fregola and Levantine moghrabieh are the same idea at a bigger size. Every one of them is wheat.
Because of where it sits. In the shop it is shelved with the quinoa and the bulgur and the freekeh; on a menu it arrives as a bed under something, in the slot a grain would occupy. Somebody newly diagnosed learns to sort grains into safe and unsafe, approaches couscous as a grain question, and the answer they are looking for is in a different category entirely. It is closer to spaghetti than to rice.
Treat couscous as pasta and the rest follows. On a menu, assume wheat unless the kitchen says otherwise, and be aware that a kitchen steaming couscous over a stock pot is cooking with it in the air and the water. Tabbouleh is the usual companion mistake: that is bulgur, also wheat. The grain-shaped things in that part of the menu that genuinely are safe are rice, quinoa, millet and buckwheat.
CiCi classes couscous as a gluten grain outright rather than something to check, because unlike oats or starch there is no version of plain couscous that is not wheat. Nothing about the surrounding product changes that verdict.
Point CiCi at the barcode on the product you're holding and get this same reasoning in about two seconds, plus the carbs and the full nutrition panel. 360,000+ packaged foods are already read and waiting.
The aisle guides below cover Couscous in context — which is usually the more useful question, because an ingredient rarely appears alone.
This answer comes from CiCi's ingredient lexicon — the same rules the scanner uses, not a separate article. Where reputable sources disagree, CiCi takes the conservative position and says so.