Against a backdrop of limited research focusing on dark-side characteristics in alliances, the authors argue that Machiavellianism in an alliance influences strategies pertaining to gaining new knowledge and using power to achieve better performance effectiveness. They develop a model using theories-in-use procedures and drawing from both Machiavellian intelligence and achievement goal perspectives, which they test in a quasi-longitudinal study of 199 marketing alliances. The results suggest that Machiavellianism relates negatively to collaborative learning and positively to learning anxiety and use of power. The findings also indicate that collaborative learning enhances performance, whereas learning anxiety and use of power result in underperformance. Collaborative learning, learning anxiety, and use of power fully mediate Machiavellianism's impact on performance. Finally, Machiavellianism's relationships with collaborative learning and learning anxiety are moderated positively and negatively, respectively, by partners’ collaborative history. This evidence provides managers with a more in-depth understanding about the nature, functioning, and performance relevance of Machiavellianism in alliance partnerships.