Objective:　Researches　about　the　association　between　serum　albumin-to-globulin　ratio　(AGR)　and　the　prognosis　of　lung　cancer　are　limited.　We　aimed　to　investigate　the　relationship　between　AGR　and　overall　survival　(OS)　in　patients　with　advanced　non-small-cell　lung　cancer　(NSCLC)　treated　with　anlotinib.　Methods:　A　retrospective　cohort　study　was　conducted　on　196　advanced　NSCLC　patients　with　anlotinib　treatment　between　June　1,　2018　and　June　1,　2021.　The　exposure　was　AGR,　calculated　by　baseline　serum　albumin　/　(serum　total　protein　-　serum　albumin).　The　outcome　was　OS,　defined　as　the　period　from　the　date　of　initial　treatment　with　anlotinib　to　death　or　the　last　follow-up.　The　univariate　and　multivariate　linear　regression　models　and　generalized　additive　models　(GAM)　were　used　to　analyze　the　relationship　between　AGR　and　OS.　The　Kaplan-Meier　method　was　used　to　analyze　the　OS.　Results:　After　adjusting　for　potential　confounders,　a　non-linear　relationship　was　observed　between　AGR　and　OS,　which　had　an　inflection　point　of　1.24.　The　hazard　ratio　and　the　confidence　intervals　on　the　left　and　the　right　sides　of　the　inflection　point　were　13.05　(0.52　to　327.64)　and　0.20　(0.07　to　0.57),　respectively.　It　suggested　that　AGR　was　positively　associated　with　OS　when　AGR　was　larger　than　1.24,　for　every　1　unit　increase　in　AGR,　the　risk　of　death　lowered　approximately　by　80%.　Conclusions:　The　relationship　between　AGR　and　the　OS　for　advanced　NSCLC　patients　with　anlotinib　is　non-linear.　AGR　level　is　an　independent　protective　factor　for　OS　in　advanced　NSCLC　patients　who　received　anlotinib　therapy.　©　2023,　The　Author(s).