["British Journal of Management, EarlyView. ", "\nAbstract\nResearch on business angels’ (BAs) investment decisions has largely focused on economic considerations, while the role of sustainability factors remains underexplored. This study examines how BAs respond to entrepreneurs’ sustainability communication. Drawing on a metric conjoint experiment with 68 BAs, we compare the effectiveness of high credibility, resource‐intensive sustainability signals such as certificates with that of low‐cost sustainability claims. Our findings indicate that BAs generally place greater value on credible sustainability signals than on claims. This preference is especially pronounced among green BAs—those with experience investing in sustainable ventures—whereas sustainability claims appear to be interpreted more flexibly across different types of BAs. At the same time, sustainability signals are more likely than claims to be penalized when they contradict a venture's prior sustainability practices, such as associations with environmentally questionable suppliers. These findings highlight the trade‐offs inherent in sustainability communication and demonstrate that entrepreneurs are more likely to attract early‐stage investment when their sustainability efforts are perceived as both credible and authentic.\n"]