Antimony　sulfide　(Sb2S3)　is　a　promising　wide-bandgap　photovoltaic　material,　and　a　potential　top-cell　candidate　for　next-generation　Si-based　tandem　solar　cells.　The　most　widely　used　electron　transport　layers　in　Sb2S3　solar　cells　are　TiO2　and　CdS,　which　present　an　obvious　performance　variation　in　open-circuit　voltage　(V　OC)　and　short　current　(J　sc).　However,　the　mechanisms　behind　the　performance　disparity　because　of　the　electron　transport　layer　(ETL)　have　not　been　disclosed.　Herein,　a　comprehensive　comparative　study　of　using　TiO2　and　CdS　as　the　electron　transport　layers　in　Sb2S3　solar　cells　is　presented,　which　covers　their　influence　on　preferential　crystal　orientation,　band　alignment,　interface,　and　bulk　defects.　It　is　found　that　the　CdS　ETL　results　in　less　interfacial　defects　and　more　favorable　band　alignment,　enabling　a　higher　V　OC,　while　the　high　resistance　of　the　CdS　film　and　parasitic　light　absorption　restricts　the　J　SC.　The　findings　provide　a　substantial　guidance　on　device　optimization　for　Sb2S3　solar　cells.　©　2022　The　Authors.　Solar　RRL　published　by　Wiley-VCH　GmbH.