Objective To evaluate complaints from patients, their families, and caregivers concerning nursing and midwifery care using the Healthcare Complaints Analysis Tool. Methods A prospective cross-sectional study with data coded against the domains and categories outlined in the Healthcare Complaints Analysis Tool. Complaints were received between June and December 2020 to nursing and midwifery services of a health service in Melbourne, Australia. Data were extracted, and complaints de-identified. The content was analysed using the Healthcare Complaints Analysis Tool, including three main domains and seven problem categories. Results A total of 69 written complaints were received: 45% were from patients, 49% from family members, and 6% from friends. Coding of complaints against the taxonomy in the Healthcare Complaints Analysis Tool resulted in 214 complaint categories. Almost half (49.5%) of the complaints pertained to the Relationship domain (including aspects of Patients' Respect and Rights, Communication, and Listening), 34.6% to the Clinical domain and 15.9% to Management. The severity of the incidents described in the complaints were: 32.6% low severity, 51.6% medium severity, and 15.8% high severity. Despite having been categorised by the health service as relating to nursing or midwifery, 38% included other healthcare professionals, and 13% of the complainants (n = 9) did not refer to nurses or midwives at all. Conclusions Assessing consumer complaints with a validated taxonomy may offer ways to target areas of care and service provision that need improvement and highlight other areas performing well. Ongoing data collection and analysis may also inform training and information needs at the individual or service management level.