Preheat the oven to 425 degrees F (220 degrees C). Line a baking sheet with parchment paper.

Stir olive oil, harissa, honey, and salt together in a large bowl.

Trim and peel carrots. If carrots are larger than 3/4-inch in diameter, cut in half lengthwise. Toss carrots in harissa mixture until coated. Spread carrots in a single layer on the prepared baking sheet.

Roast in the preheated oven for about 20 to 25 minutes, flipping halfway. The carrots should be tender with some caramelized edges. Transfer to a serving dish and garnish with parsley.