Gd55-xHoxAl25Co20　(x　=　5,10,15,20,　in　at.　%)　metallic　glass　(MG)　with　a　diameter　of　5　mm　were　successfully　fabricated.　Substituting　Gd　by　Ho　improves　thermal　stability,　manifested　by　respective　shifts　of　the　glass　transition　temperature,　the　crystallization　onset　temperature,　and　the　peak　crystallization　temperature　to　higher　temperatures.　The　apparent　activation　energies　for　the　glass　transition　and　for　crystallization　initially　increase　with　Ho　content,　and　then　begin　to　decrease　at　higher　Ho　contents.　All　four　amorphous　alloys　show　excellent　soft　magnetic　properties,　transitioning　from　a　ferromagnetic　state　to　a　paramagnetic　state　as　temperature　increases.　Arrott　curves　with　a　positive　slope　indicated　a　second-order　magnetic　transition　in　all　four　MGs.　Ho　addition　is　beneficial　to　isothermal　entropy　change　(|ΔSM|)　and　refrigeration　capacity　(RC),　although　the　values　of　the　Curie　temperature　and　the　product　RC　progressively　decrease　with　increasing　Ho　content.　Gd50Ho5Al25Co20　MG　shows　the　best　combination　of　magnetocaloric　properties　with　a　maximum　|ΔSM|　of　9.53　J·kg−1·K−1,　a　RC1　(the　product　of　the　peak　entropy　change　and　the　full　width　at　half　maximum　of　the　peak)　of　817.77　J·kg−1,　and　a　RC2　(integrating　the　area　under　the　|ΔSM|　versus　temperature　curves)　of　674　J·kg−1　with　a　field　change　of　0–5　T　(0–3980　kA·m−1).　©　2024　Elsevier　B.V.