Due to the rising prices of houses and rent, apartment buildings have become the preferred and most utilized dwellings in Australia. However, there have been cases of serious defects in multi-unit dwellings (apartment buildings), posing various risks to and reducing potential residents’ confidence in such dwellings. To address this issue, the current study investigated the types, causes, risk severity, and impacts of defects on residents in mid- to high-rise multi-unit dwellings in Australia. The study utilized a mixed approach involving quantitative (online questionnaire) and qualitative (interviews) methods. Data were collected from 104 apartment building residents in Brisbane, Queensland, Australia, with support from interviews with six experienced local construction professionals. The results revealed that there are 11 key defects present in local apartment buildings, with waterproofing, internal finishes, and structural issues being the most frequently reported. Residents typically report these defects to building owners, agents, and managers, who take more than three months, on average, to rectify them, adding to the residents’ psychological issues and their inability to use the property as intended. The reasons for the delayed rectification of defects include non-responsive owners, agents, and building management teams, scheduling conflicts, litigation, and high costs. The interviewed professionals acknowledged the presence of defects and identified the reliance on Design and Construct (D&C) and fixed price contracts, lack of public awareness, and absence of a system to capture builders’ reputation, as well as a manipulative quality check system, as key reasons for defects. This study addresses the defect concerns in multi-unit Australian dwellings (apartments) and expects to spark a much-needed debate around reforms in the construction sector to address these issues and minimize their risks and impact on residents.