Yes, cauliflower is a great low-carb vegetable in your keto diet. Cauliflower is a popular low carb vegetable since it can be substituted for potatoes in many recipes. Compared to broccoli or radishes, cauliflower is low in calories and carbohydrates and has a moderate flavor. In addition, cauliflower can replace high-carb ingredients for making hummus, rice, or mashed potatoes.