Objective: The early intervention service (EIS) model for psychosis has been implemented with increasing fre-quency; yet, improving outcomes across domains for all patients remains challenging. Measurement-based care can strengthen outcomes by optimizing interventions and promoting alignment with standards, but it is still not widely deployed in EIS. The authors conducted a scoping review by systematically identifying and synthesizing measures used in EIS related to purpose (i.e., to assess patients, families, and programs), domains (e.g., symptoms, quality of life), and reporting perspectives (of patients, families, and clinicians).Methods: EMBASE, MEDLINE, PsycINFO, CINAHL, and Cochrane Library databases were searched for pertinent lit-erature published between 2000 and 2020. Two re-viewers independently screened titles, abstracts, and full texts and extracted data. Measures were classified as clinician-reported outcome measures (CROMs), patient -reported outcome or experience measures (PROMs/PREMs), or family-reported outcome or experience mea-sures (FROMs/FREMs). Results: In total, 172 measures of 27 domains were identified from 115 articles. Nineteen measures had been used to as-sess programs on fidelity, service engagement, and satis-faction; 136 to assess patients on duration of untreated psychosis, symptoms, functioning, quality of life, and others; and 17 to assess families on coping and burden, background, and others. Sixty percent were CROMs, 30% were PROMs/ PREMs, and 10% were FROMs/FREMs.Conclusions: Greater inclusion of PROMs and FROMs is needed because they align with the EIS philosophy of patient and family engagement and may improve shared decision mak-ing and outcomes. A comprehensive, meaningfully synthesized archive of measures can advance measurement-based care, services research, and data harmonization in early psychosis.