Rubuta ci gaba don wannan sakin layi - A ranar 23 ga Agusta, 2015, Bonaventura ya fara buga kakar wasa ta farko yayin da Milan ta yi rashin nasara 2<unk>0 a hannun Fiorentina. A wasan da ya biyo baya da Empoli, Bonaventura ya shigo filin a matsayin wanda ya maye gurbin Suso a minti na 55 kuma ya sami damar taimakawa Luiz Adriano ya ci nasara daga kusurwar kusurwa minti 15 daga baya. A ranar 19 ga Satumba, Bonaventura ya taimaka wa burin farko na Carlos Bacca kuma ya zira kwallaye kai tsaye daga bugun fansa a nasarar 3<unk>2 a kan Palermo. Ya kuma sami wani taimako da burin a wasan Milan na gaba, nasarar 2 × 3 a kan Udinese. Bugu da ƙari, ya taimaka wa burin Carlos Bacca da Philippe Mexès a kan Lazio a cikin nasara 3 × 1 a ranar 1 ga Nuwamba. Ya ci gaba da yin aiki mai kyau a karkashin kocin kungiyar Siniša Mihajlović kuma ya zama muhimmin dan wasa ga tawagarsa a duk tsawon kakar. Bayan ya rasa wasan da ya yi da tsohuwar kungiyarsa ta Atalanta ta hanyar dakatar da shi, sai ya zira kwallaye a wasan farko a wasan da suka doke Sampdoria da 4-1. Ya sake zira kwallaye a wasansa na gaba a ranar 1 ga Disamba, cin nasarar 3<unk>1 Coppa Italia na Crotone, ta hanyar bugun fansa mai tsayi 20. A ranar 20 ga Disamba ya taimaka wa burin Carlos Bacca kuma ya zira kwallaye a ƙarshen lokacin da Milan ta doke Frosinone 4-2. A ranar 17 ga Janairu 2016, ya ba da wani taimako ga Carlos Bacca yayin da Rossoneri ta doke Fiorentina 2 <unk> 0. Ya ƙare kakar wasa tare da kwallaye 7 da taimakawa 8 a duk gasa yayin da Milan ta gama 7 a Serie A
, kuma ya yi rashin nasara a wasan karshe na Coppa Italia da Juventus, bayan shan kashi 1-0 a cikin karin lokaci.