Purpose To determine the normative values and reference equations of the 4-Meter Gait Speed Test (4MGS) at usual and maximal speed for Portuguese adults. We also assessed the participant experience during the performance of the 4MGS. Materials and methods A cross-sectional study was conducted with individuals without disabilities. Sociodemographic, anthropometric, smoking habits and physical activity (Brief Physical Activity Assessment Tool [BPAAT]) data were collected. Individuals performed 3 repetitions of 4MGS at usual and maximal speeds, and the best performances were recorded. Speed values were calculated by age and sex. Stepwise multiple regressions were used for the reference equations. Participants rated their comfort from 0 (‘not comfortable at all’) to 5 (‘very comfortable’) for each modality and indicated their preferences. Results A total of 287 individuals (62.4% female; 47.8 ± 19.5 years) were recruited. Speed was significantly reduced after the sixth decade of life compared with the other decades (p < 0.001). Reference equations were: Usual speed = 1.598 – (0.006 x age) + (0.060 x BPAAT classification), R2= 27% and Maximal speed = 2.272 – (0.010 x age) + (0.157 x sex) + (0.73 x BPAAT classification), R2= 38%. Most participants felt ‘very comfortable’ performing the 4MGS at usual speed (94.8%), maximal speed (75.6%) and no preference in 4MGS modalities (69%). Conclusions Speed is significantly affected by age. For the reference equations, age and physical activity explain the results of usual speed, and both associated with sex explain the results of maximal speed. Most participants were highly comfortable and expressed no preference in 4MGS modalities.