To uncover and analyze conceptualizations of cross-institutional collaboration in engineering education, a systematic review study was conducted, identifying commonalities in frameworks, assessments and evaluations, and challenges across prior studies. 74 papers were reviewed, revealing "study descriptors," "theoretically applied frameworks," "outcomes of assessments and evaluations," and "common challenges." The findings indicate that the concept of cross-institutional collaboration in engineering education is region-specific, with papers most frequently originating from the US. The outcomes identified also highlight the difficulty in establishing clarity among outcomes based on assessments and evaluations, since the majority of the reviewed papers do not include empirical data gathered outside the collaborative activities. The structural and personal challenges and barriers found underline the need for more efforts to ensure successful collaboration with and across engineering education. Finally, designing, delivering, and sustaining collaboration require further attention from decision-makers in engineering education to address and facilitate collaboration between academic staff and students across institutions.