Undertaking various activities aimed at sustainable development, especially energy conservation, is becoming one of the challenges of modern economies, including developing urban areas. One of the most widely promoted activities is designing and implementing energy-conserving solutions for urban mobility. People play a vital role in this regard, especially young people, represented here by Generation Z. Their attitudes and behaviours regarding sustainability can significantly impact the effectiveness of energy-efficient technological solutions. The purpose of this article is to examine the nature of the relationship between the assessment of the importance of energy-efficient transportation solutions available in the city and the attitudes and behaviours of representatives of Generation Z relating to the idea of sustainability, broken down into two categories, i.e., energy-conserving behaviour and mobility. In this study, a diagnostic survey method was used. Based on the literature review, we designed a research tool in the form of a questionnaire. Four hundred and ninety representatives of Generation Z participated in the study. To verify the hypotheses, first, a qualitative analysis was carried out for the three study areas using measures of central tendency; then, a correlation analysis was performed based on Pearson’s chi-square independence test, and to determine the strength of the relationship, the following symmetric measures were used: Cramer’s V and the Contingency Coefficient. The normalisation of the data, giving them a quantitative character, allowed the possibility of examining the correlation using Pearson’s test and the directionality of the analysed relationships based on simple and multiple linear regression results. Ananalys is of the obtained results allows us to conclude that energy-related sustainable behaviours in the acquisition of electrical appliances, their use and disposal, and mobility-related energy-conserving behaviours, resulting from the choice of means of transportation for moving in the city, influence the assessment of the importance of available energy-efficient mobility solutions. City administrations could use the study results as a guideline for the implementation of energy-conserving solutions in urban transportation, as well as the planning and promotion of appropriate activities related to the mobility of Generation Z, that are adequate to the attitudes and behaviours of young people.