The purpose of this meta-analysis was to compare the fusion rate and outcomes directly between patients who underwent stand-alone lateral lumbar interbody fusion (LLIF) and LLIF with supplemental posterior instrumentation. A comprehensive literature search was performed for relevant studies using PubMed, EMBASE, Web of Science, and Cochrane Library. The stand-alone and instrumented LLIF were compared by the fusion rate, the radiographic parameters, the cage subsidence rate, the clinical outcomes, the complication rate, and the reoperation rate. A total of 13 studies comprising 1090 patients with lumbar degenerative disease (LDD) were included. There was no significant statistical difference in the complication rate, and there was no significant clinical difference in the improvement of clinical outcomes at the last follow-up between patients who underwent stand-alone and instrumented LLIF. Nevertheless, lower fusion rate (RR, 0.92; 95% CI 0.87 to 0.98, P = 0.006), inferior restoration of disk height (WMD, -0.68; 95% CI -1.04 to -0.32, P < 0.001) and segmental lordosis (WMD, -1.28; 95% CI -2.30 to -0.27, P = 0.013), higher cage subsidence rate (RR, 1.68; 95% CI 1.36 to 2.07, P < 0.001), and higher reoperation rate (RR, 2.12; 95% CI 1.02 to 4.43, P = 0.045) were observed in the stand-alone group. Both stand-alone and instrumented LLIF were effective in improving the clinical outcomes of patients with LDD. However, the stand-alone LLIF was associated with lower fusion rate, inferior maintenance of indirect decompression, and higher reoperation rate due to high-grade cage subsidence. For patients with risk factors of high-grade cage subsidence, the LLIF with posterior instrumentation may be the better choice.