In theory, usability work is an important and well-integrated activity in developing software. In practice, collaboration on improving usability is ridden with challenges relating to conflicting professional goals, tight project schedules, and unclear usability findings. The authors study those challenges through 16 interviews with software developers, usability experts, and project managers. Four themes that are key challenges to successful interaction between stakeholders are identified: poor timing when delivering usability results, results lacking relevance, little respect for other disciplines, and difficulties sharing important information. The authors review practices that have successfully addressed these challenges and discuss their observations as encompassing multiple perspectives and as a collaborative cross-professional learning process