BACKGROUND: The Determinants of Implementation Behavior Questionnaire (DIBQ) measures facilitators or barriers of healthcare professionals implementation behaviors based on the current implementation research on practice and policy. The DIBQ covers 18 domains of the Theoretical Domains Framework and consists of 93 items. A previously tailored version (DIBQ-t) covering 10 domains and 28 items focuses on implementing best-practice low back pain care. AIM: To tailor a shortened version of DIBQ to multiprofessional rehabilitation context with cross-cultural adaptation to Finnish language. DESIGN: A two-round Delphi study. SETTING: National-level online survey. POPULATION: Purposively recruited experts in multiprofessional rehabilitation (N.=25). METHODS: Cross-cultural translation of DIBQ to Finnish was followed by a two-round Delphi survey involving diverse experts in rehabilitation (physicians, physiotherapists, occupational therapists, psychologists, nursing scientists, social scientists). In total, 25 experts in Round 1, and 21 in Round 2 evaluated the importance of DIBQ items in changing professionals implementation behavior by rating on a 5-point Likert Scale (1 = Strongly Disagree, 5 = Strongly Agree) of including each item in the final scale. Consensus to include an item was defined as a mean score of >= 4 by >= 75% of Delphi participants. Open comments were analyzed using inductive content analysis. Items with agreement of <= 74% were either directly excluded or reconsidered and modified depending on qualitative judgements, amended with experts suggestions. After completing an analogous second-round, a comparison with DIBQ-t was performed. Lastly, the relevance of each item was indexed using content validity index on item-level (I-CVI) and scale-level (S-CVI/Ave). RESULTS: After Round 1, 17 items were included and 48 excluded by consensus whereas 28 items were reconsidered, and 20 items added for Round 2. The open comments were categorized as: 1) "modifying"; 2) "supportive"; and 3) "critical". After Round 2, consensus was reached regarding all items, to include 21 items. After comparison with DIBQ-t, the final multiprofessional DIBQ (DIBQ-mp) covers 11 TDF domains and 21 items with I-CVIs of >= 0.78 and S-CVI/Ave of 0.93. CONCLUSIONS: A Delphi study condensed a DIBQ-mp with excellent content validity for multiprofessional rehabilitation context. CLINICAL REHABILITATION IMPACT: A potential tool for evaluating determinants in implementing evidence-based multiprofessional rehabilitation interventions.