A serious problem in the workplace is incivility, which impacts especially vulnerable groups like single mothers who hold jobs and experience subtle unfair or damaging treatment. As the number of single working mothers continues to rise in today’s workforce, this study aims to clarify third-party perceptions about incivility against them at work and subsequent influences on individuals as well as the organization. Because the analysis is embedded in theories of social role expectations and organizational justice, it explores third-party observers’ perceptions (such as coworkers or supervisors) of whether incivility directed at single working mothers differs from that experienced by their comparison group—professionally equivalent peers who do not share equal caregiver responsibilities. The researchers employed a mixed-methods approach, incorporating both quantitative surveys and in-depth qualitative interviews to collect rich data from participants who represented several fields. They report their results that third-party observers are less likely to experience vicarious justification of incivility against single working mothers but may be equally unlikely or even more reluctant than in the case of other employees and furthermore find this data account for these differences. The results illustrate the intricate interplay of gender, family structure and work dynamics on workplace outcomes—all leading to lower job satisfaction rates, a high level of stress or even stagnation in career progression for single working mothers. Our findings also extend the workplace incivility literature by demonstrating ways in which single working mothers are particularly vulnerable to this form of mistreatment and a broader need for organizational policies that cultivate an inclusive, supportive environment. Implications for human resource management, organizational culture and policy based on these findings are discussed as it may provide some recommendations for handling incivility in the workplace environment.