The construction of existing self-report measures of inner speech is guided by a priori theoretical views regarding how it is experienced or what functions it serves. We present two studies aimed at constructing and validating a more ecologically valid tool called the General Inner Speech Questionnaire (GISQ). Study 1 employed an open-format thought-listing procedure inviting 227 participants to freely recall what they talk to themselves about in general. The most frequently self-generated inner speech instances were about negative emotions, problem solving/thinking, planning, self-motivating, emotional control, and self. In Study 2, we used this inner speech content to construct the 57-item GISQ. The GISQ is normally distributed, shows acceptable internal consistency, and contains four moderately strong factors: self-reflection, self-observation, cognition, and inner speech accompanying activities. Importantly, the GISQ correlates positively with other measures of inner speech and self-related processes.