Background <p>Work plays an important role in supporting employees to enjoy mental wellbeing and a sense of purpose and meaning while contributing to productive workplaces. However, some employees experience suicidal distress while working. When disclosing suicidal distress to seek and receive help, employees may face barriers in receiving compassionate and supportive responses. Integrated workplace mental health approaches emphasise protecting and promoting good mental health by addressing workplace factors. This study aimed to develop best practice guidelines to assist workplaces (e.g., employers, managers, human resources and work health and safety staff) to support employees who disclose suicidal distress while working.</p> Methods <p>The Delphi expert consensus method was used to develop best practice guidelines inclusive of necessary actions to support employees experiencing suicidal distress while working. We conducted systematic searches of scientific and grey literature and combined these with statements extracted from a recent qualitative study to form a questionnaire. We recruited participants onto two expert panels (employees with lived experiences of suicidal distress (<i>n</i> = 24) and professionals (<i>n</i> = 21) who rated the importance of 185 statements across three questionnaire rounds. Statements that were endorsed by at least 80% of both panels were included in the guidelines.</p> Results <p>The two expert panels endorsed 141 out of the 185 statements, spanning six thematic sections from workplace systems through to employee responsibilities. There were consistently high levels of agreement between and within the two panels relating to culture and leadership and psychosocial safety actions. Areas of disagreement between the two panels related to statements in Sect. 1 - <i>Workplace systems</i> (co-design) and Sect. 4 - <i>Education and training</i> (employee training).</p> Conclusions <p>By using the Delphi approach, we have developed a novel set of best practice guidelines to assist workplaces (e.g., employers, managers, and human resources and work health and safety staff) to implement actions to support employees disclosing suicidal distress while working. As next steps, we recommend evaluating the feasibility of implementing the guidelines across a range of settings, occupations and industries, including in workplaces that vary in size and with employees with a range of intersecting concealable identities, including experiencing suicidal distress.</p>