Objective <p>To investigate the efficacy of deproteinized bovine bone mineral (DBBM) associated with injectable platelet-rich fibrin (i-PRF) in horizontal maxillary regeneration.</p> Materials and methods <p>Edentulous maxillary patients indicated for horizontal bone regeneration prior to implant placement were included in a split-mouth randomized clinical trial. The tested bone grafts were: DBBM alone (Control group) and i-PRF + DBBM (i-PRF group). Bone width gain was measured with digital tomographs taken before surgery, 72&#xa0;h after surgery, and 6 months postoperatively. Twelve months after implant placement, peri-implant bone changes were measured with periapical radiographs; keratinized tissue width, probing depth, plaque index, bleeding on probing, suppuration, and recession were evaluated. The implant success rate was also recorded. The data were submitted to two-way repeated measures analysis of variance (ANOVA) and Bonferroni’s test (bone width and peri-implant bone changes), Student’s t-test (peri-implant soft tissue), and Fisher’s exact test (categorical data).</p> Results <p>A total of 18 patients were included in the study. Bone widths were significantly greater at the postsurgical and six-month timepoints compared with baseline for both graft techniques (<i>p</i> &lt; 0.05). No significant differences were observed between control and i-PRF groups in bone width gain (<i>p</i> &gt; 0.05), implant success (<i>p</i> = 0.510), peri-implant bone changes (<i>p</i> = 0.509), and outcomes of peri-implant soft tissues (<i>p</i> &gt; 0.05).</p> Conclusion <p>The association of DBBM with i-PRF showed similar outcomes compared with DBBM alone for the studied parameters.</p> Clinical significance <p>In edentulous maxilla with insufficient bone width (≤ 4&#xa0;mm), where cancellous bone is present, both the association of i-PRF+DBBM and DBBM alone were effective in providing bone width gain for implant placement.</p> Clinical trial registration <p>https//ensaiosclinicos.gov.br/rg/RBR10m7c788.</p>