Aim: To identify, describe and analyse the gender perspective in the use of the diagnoses contained in the NANDA-I taxonomy in observational studies published in the scientific literature. Design and methods: A systematic review has been conducted spanning from 2002 to 2020. The most frequent NANDA-I nursing diagnoses in care plans reported in observational studies, and the defining characteristics and related factors identified for men and women have been described. The Preferred Reporting Items for Systematic Reviews (PRISMA-P) have guided our research. The main findings have been summarized using a descriptive narrative synthesis approach. Results: Forty-one articles were included in our study. With regard to gender analysis, the percentage of men and women that make up the sample were not specified in all articles, and half of the studies did not identify gender either in the diagnosis label or in their defining characteristics or related factors. Based on the reviewed articles, gender perspectives are not systematically incorporated in the use of the NANDA-I diagnosis. Therefore, gender biases in its use in the scientific literature may exist. This situation poses barriers to determine the health responses that are different and unequal between women and men.