Background <p>Variations in soft tissue thickness related to age and gender are clinically significant for addressing facial aging and planning esthetic interventions. Previous studies have assessed skin thickness using various methods, including ultrasonography and biopsies, but data specifically examining forehead soft tissue thickness by age and gender are limited.</p> Objective <p>This study aimed to investigate the effects of age and gender on forehead soft tissue thickness using MRI, a non-invasive modality that provides excellent contrast resolution and reliable measurements.</p> Methods <p>We conducted a retrospective analysis of 160 Caucasian adults (80 females, 80 males) aged 20–99 years, grouped by decade. We measured midline and lateral forehead soft tissue thickness in the sagittal plane on T1-weighted MRI sections, from skin to external cortical lamina, in the lower, middle, and upper thirds. Statistical analyses were performed using factorial ANOVA to assess the impact of age and gender.</p> Results <p>Males had significantly greater forehead soft tissue thickness than females at all ages and across most regions. Notable differences were observed in the midline (5.4 mm in males vs. 5.0 mm in females; <i>p</i> = 0.043) and in the lower third of the lateral forehead (9.4 mm in males vs. 8.6 mm in females; <i>p</i> = 0.008). Thickness increased from the third to the fifth decade, peaking between ages 40–49, then declining in later decades, particularly in the lower third.</p> Conclusion <p>Forehead soft tissue thickness varies significantly by age and gender, highlighting the importance of considering these differences in planning esthetic procedures for optimal outcomes.</p> Level of Evidence IV <p>This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors <a href="http://www.springer.com/00266">www.springer.com/00266</a>.</p>