The　reliable　design　of　the　high-performance　column　made　of　fiber　reinforced　polymer　(FRP)-confined　engineered　cementitious　composites　(ECC)　necessitates　a　clear　understanding　of　the　size　effect　under　axial　compression.　This　paper　presents　the　compressive　behaviors　of　glass　FRP　(GFRP)　and　large　rupture　strain　(LRS)　polyethylene　terephthalate　(PET)　FRP-confined　ECC　columns.　The　specimen　size,　confinement　level,　and　FRP　type　were　the　variables.　Five　diameters　of　100,　200,　300,　400,　and　500　mm　were　designed　to　cover　a　wide　size　range.　Results　showed　that　both　the　compressive　strength　and　ductility　of　ECC　were　substantially　improved　with　FRP　confinement.　Compared　with　GFRP-confined　ECC,　PET　FRP-confined　ECC　exhibited　higher　ductility.　The　key　stresses,　namely　initial　peak　stress,　post-peak　ravine　stress,　and　ultimate　stress　decreased　with　increasing　specimen　size.　Nevertheless,　the　specimen　size　had　a　marginal　influence　on　the　key　strains　and　dilation　behavior.　After　evaluating　the　existing　size-dependent　ultimate　strength　models　of　FRP-confined　concrete,　a　new　expression　for　predicting　the　ultimate　strength　of　FRP-confined　ECC　was　introduced,　which　was　shown　to　fit　well　with　the　test　results.　©　2022　Elsevier　Ltd