A checklist of the Collembola of the Collo massif in northeastern Algeria, the wettest region of northern Africa, is presented, based on the results of sampling campaigns carried out from 2011 to 2017. Before this work, only four species were reported from Collo in the literature. The Collembola of the massif include now a total of 74 species, in 53 genera and 17 families. Of the 74 recorded species, 26 are new for Algeria, and at least four are new to science and will be described in forthcoming papers. The most remarkable discoveries include an undescribed Pseudachorutinae Borner, 1906 provisionally assigned to the tropical genus Kenyura Salmon, 1954; Sensillanura austriaca (da Gama, 1963) a Neanurinae Borner, 1901, so far only known from the northern Alps; a second undescribed species of the so far monospecific Neanurinae genus EdoughnuraDeharveng, Hamra-Kroua & Bedos, 2007; the first record of the genus Subisotoma Borner, 1901 in Algeria (Isotomidae Borner, 1913); an undescribed species of the genus Pseudosinella Schaffer, 1897, close to the recently described P. najtae Jordana, Barranco, Amezcua & Baquero, 2017 from Spain and remarkable by the ciliation of all its labral chaetae (Entomobryidae Tomosvary, 1882). This inventory makes the Collo massif the richest spot of Collembolan diversity today in Algeria. It also illustrates how large are the geographical gaps in our knowledge of the Algerian fauna.