This document is a guide detailing the Test Maturity Assessment, which is a structured evaluation aimed at measuring the maturity of an organization’s testing processes. It outlines the assessment's objectives, which include providing insights into the organization’s testing activities and their integration within software development and quality assurance practices. The guide describes the various phases of the assessment, starting with the Kick-off & Discovery phase, which involves initial alignment on prerequisites and gathering information on the current test scope. It continues with the Discovery Review, where initial findings are shared, followed by an in-depth analysis of test-related processes. The final phase includes Closing & Reporting, where conclusions and action items are presented. The document also specifies the requirements for participation in the assessment and the expected outcomes, including optimization propositions and improvement actions tailored to enhance software quality and reliability.