Background The ability of Ga-68-DOTA-SSTR to detect the primary sites of neuroendocrine tumors (NETs) remains undetermined, and the clinical benefit of this imaging agent is not clear. Purpose To evaluate the diagnostic accuracy of Ga-68-DOTA-SSTR for carcinoma unknown primary (CUP) neuroendocrine tumors and to further analyze the detection rate of Ga-68-DOTA-SSTR for primary and metastatic sites. Material and Methods A comprehensive literature search of PubMed/MEDLINE and ScienceDirect was performed in October 2019 in accordance with the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines. We critically reviewed all studies based on the PICOS criteria. QUADAS-2 was used to evaluate the quality of the methodology of the included studies. Results A total of 10 studies (484 patients, mean age = 56.6 +/- 4.3 years) were included in the study. The pooled sensitivity and specificity of Ga-68-DOTA-SSTR in identifying CUP-NETs were 82% and 55%, respectively. The area under the receiver operating characteristic curve was 69%. Regarding metastasis sites, Ga-68-DOTA-SSTR found the most metastases in the liver (57.9%), followed by the lymph nodes (22.8%), bones (12.8%), lung (2.8%), and others (1.7%). The pooled detection rate of Ga-68-DOTA-SSTR for CUP-NETs was 61%. Conclusion The present study demonstrated the high diagnostic sensitivity of Ga-68-DOTA-SSTR for CUP-NETs. Ga-68-DOTA-SSTR PET/CT was highly effective in locating the primary and metastatic sites of CUP-NETs.