The slope of a supply curve is positive. A supply curve is a graphical representation of the relationship between the quantity of a good or service that a producer is willing to offer for sale and the price of that good or service. The slope of the supply curve indicates how much the quantity supplied changes when the price changes. In general, the higher the price of a good or service, the more the producer is willing to supply. Therefore, the supply curve slopes upward from left to right, indicating a positive slope.