We aimed to develop a questionnaire that assesses the impact of pelvic pain on women, regardless of diagnosis, that has high utility, sound psychometric performance, easy scoring, and high reliability. Two studies, with 3 separate cohorts, were undertaken. Both studies were completed online. Studies included women with self-reported pelvic pain. Women were eligible to participate regardless of whether their pelvic pain was undiagnosed, self-diagnosed, or diagnosed by a clinician. Study 1 used a 3-round "patient-as-expert" Delphi technique. These rounds defined the 10 aspects of life with the self-reported greatest impact on the lives of women with pelvic pain, which formed the questionnaire. Study 2 used Rasch analysis to assess the psychometric properties of the resultant 10-item questionnaire. To assess its reliability, a subgroup completed the questionnaire 3 times over a 3-week period. In study 1, 443 women with pelvic pain participated. The resultant 10-item questionnaire consisted of 8 Likert questions and 2 supplemental, nonscored questions. In study 2, 1203 women with pelvic pain completed the questionnaire. Rasch analysis showed that the questionnaire targeted the pelvic pain population well, had appropriate Likert categories, constituted a unidimensional scale, and showed internal consistency. Twenty-seven women with pelvic pain completed the reliability trial. Test-retest reliability was high (intraclass correlation coefficient 0.91, P < 0.001). The resultant Pelvic Pain Impact Questionnaire assesses the life impact of pelvic pain. It uses patient-generated language, is easily administered and scored, has very strong psychometric properties, and it is suitable for research and clinical settings across primary, secondary, and tertiary care.