<p class="MsoNormal" style="margin-bottom: 0cm; line-height: normal;"><span lang="EN-US" style="mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin; color: black; mso-ansi-language: EN-US;">This book constitutes the refereed proceedings of the 26th International Conference on Product-Focused Software Process Improvement, PROFES 2025, held in Salerno, Italy, during December 1–3, 2025.</span></p><p class="MsoNormal" style="margin-bottom: 0cm; line-height: normal;"><span lang="EN-US" style="mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin; color: black; mso-ansi-language: EN-US;">The 23 full research papers and 20 short research papers presented in this volume were carefully reviewed and selected from 101 submissions.&#xa0;</span></p><p class="MsoNormal" style="margin-bottom: 0cm; line-height: normal;"><span lang="EN-US" style="mso-fareast-font-family: 'Times New Roman'; mso-bidi-font-family: Calibri; mso-bidi-theme-font: minor-latin; color: black; mso-ansi-language: EN-US;">PROFES 2025 focuses on professional Software Process Improvement (SPI) motivated by product, process, and service quality needs. The technical program was curated by a committee of distinguished experts in software process improvement, software process modeling, and empirical software engineering.</span><span lang="EN-US" style="font-size: 11.0pt; line-height: 115%; font-family: 'Calibri',sans-serif; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: 'Times New Roman'; mso-hansi-theme-font: minor-latin; mso-bidi-theme-font: minor-latin; color: black; mso-ansi-language: EN-US; mso-fareast-language: DE; mso-bidi-language: AR-SA;"><!--[endif]--></span></p>