Distant metastasis is a prevalent cause of mortality in gastric cancer (GC) patients. Anoikis, a process that induces cell death when cells get detached from the extracellular matrix (ECM), acts as a barrier to tumor metastasis. To survive in the circulatory system and metastasize, tumor cells must acquire anoikis resistance. It is crucial to identify the molecular processes that cause resistance to anoikis in GC since this might lead to the discovery of novel treatment targets and improve the long-term survival of GC patients. In this study, we employed quantitative proteomics to identify growth differentiation factor 15 (GDF15) as a key factor in GC anoikis resistance. We found that GDF15 enhances protective autophagy, thereby promoting anoikis resistance in GC cells. Furthermore, through DNA pull down assay, activating transcription factor 2 (ATF2) was found to be a critical regulator of GDF15 expression, acting as a transcriptional activator of GDF15. Collectively, these discoveries indicate that ATF2 and GDF15 have great potential as target candidates for developing therapeutic strategies to address the metastasis of GC.