The short version of the Bielefeld Partnership Expectations Questionnaire (BPEQ-12) assesses the partner-related attachment dimensions fear of rejection, readiness for selfdisclosure, and conscious need for care. The presented study investigated the factor structure in two samples and evaluated the convergent validity of scales. The sample included N = 175 patients with panic disorder and/or agoraphobia and N = 143 healthy controls. Besides, the BPEQ, the Experiences in Close Relationships Questionnaire (ECR), and the Brief Symptom Inventory (BSI) were assessed as well, and the Adult Attachment Prototype Rating (AAPR) was conducted. A confirmatory factor analysis of the three factor model (using a WLSMV estimator) revealed an acceptable model fit for the entire sample, patients and controls in terms of low RMSEA and SRMR (< 0.08) and high CFI and TLI (> 0.95). We found metric, scalar, and strict measurement invariance for the presence of anxiety disorder (ΔCFI ≤ –0.01 and ΔRMSEA ≥ 0.01). However, only for fear of rejection and readiness for self-disclosure the reliability was acceptable (Cronbach’s a > 0.7), and convergent validity in terms of large correlations (r > 0.7) with the ECR scales was found in both samples. The scale conscious need for care had a questionable reliability (Cronbach’s a > 0.6) and correlated only slightly with ECR-R scales. We conclude that fear of rejection and readiness for self-disclosure of the BPEQ-12 are reliable and valid scales for measuring partner-related attachment in healthy and clinical samples.