(1) Background: Vulvodynia is characterized by vulvar pain for at least three months and may have related variables, one of these being pelvic floor hypertonus. The purpose of this study was to compare the therapeutic effectiveness of two weekly sessions of pelvic floor rehabilitation and 5 mg of vaginal diazepam daily vs. pelvic floor rehabilitation alone in individuals with vulvodynia. (2) Methods: A single-center, not-blind, randomized study enrolled 20 vulvodynic patients: A total of 10 were treated with dual therapy (intravaginal diazepam and pelvic floor rehabilitation), and 10 were treated with only pelvic floor rehabilitation. All of them underwent a pelvic floor ultrasound examination and VAS pain and Marinoff scale assessments before the beginning of therapy as well as three and six months later. (3) Results: The elevator plate angle ranged from 8.2 to 9.55 (p = 0.0005), hiatal area diameter ranged from 1.277 to 1.482 (p = 0.0002), levator symphysis distance ranged from 3.88 to 4.098 (p = 0.006), anorectal angle ranged from 121.9 to 125.49 (p = 0.006), Marinoff scale ranged from 2.3 to 1.4 (p = 0.009), and VAS scale ranged from 5.8 to 2.8 (p < 0.001). (4) Conclusions: This pilot study demonstrates that the suggested treatment improves the hypertonicity of the pelvic floor, as measured by ultrasound parameters, correlating with a reduction in symptomatology.