Robin Lakoff proposed that women are more likely than men to use tentative speech forms (e.g., hedges, qualifiers/disclaimers, tag questions, intensifiers). Based on conflicting results from research testing Lakoff's claims, a meta-analysis of studies testing gender differences in tentative language was conducted. The sample included 29 studies with 39 independent samples and a combined total sample of 3,502 participants. Results revealed a statistically significant but small effect size (d = 0.23), indicating that women were somewhat more likely than men to use tentative speech. In addition, methodological moderators (operational definition, observation length, recording method, author gender, and year of study) and contextual moderators (gender composition, familiarity, student status, group size, conversational activity, and physical setting) were tested. Effect sizes were significantly larger in studies that (a) observed longer (vs. shorter) conversations, (b) sampled undergraduates (vs. other adults), (c) observed groups (vs. dyads), and (d) occurred in research labs (vs. other settings). The moderator effects are interpreted as supporting proposals that women's greater likelihood of tentative language reflects interpersonal sensitivity rather than a lack of assertiveness. In addition, the influence of self-presentation concerns in the enactment of gender-typed behavior is discussed. (Contains 1 figure and 2 tables.)