Background: Spontaneous abortion (SA) is a common pregnancy complication with challenging prediction and prevention for healthcare providers. It can lead to stress, anxiety, depression, and grief for parents. Self-talk (ST) is a communication skill with a significant role in the relationship of events and emotions and can facilitate the management of most emotional and behavioral disorders. However, there is limited information about its effects on women with SA. Objectives: The aim of this study was to assess the effects of positive ST on anxiety and grief among women with SA. Methods: This quasi-experimental study was conducted in 2021 using a two-group pre-test-post-test design. Eighty women with SA were randomly selected from a teaching hospital in Zahedan, Iran, and were alternately allocated to an intervention group and a control group on a weekly basis. Participants in the intervention group received education about positive ST in eight 20-minute sessions held twice weekly. Data were collected before and 2 months after the intervention using a demographic questionnaire, the Hospital Anxiety and Depression Scale, and the Perinatal Grief Scale. The SPSS v. 16.0 software was used to analyze the data at a significance level of < 0.05 using the Shapiro-Wilk, paired-sample and independent-sample t tests, and chi-square test. Results: The age mean of the participants was 26.40 ± 5.63 years in the intervention group and 24.45 ± 5.11 years in the control group. The groups did not significantly differ from each other respecting baseline demographic and clinical characteristics (P > 0.05). The mean scores of anxiety (control: 4.57 ± 1.98, intervention: 2.60 ± 1.59) and grief (control: 64.85 ± 22.68, intervention: 50.97 ± 16.522) significantly decreased in both groups (P = 0.001, P = 0.003), and the amount of decrease in the intervention group was significantly more than the control group (P < 0.05). Accordingly, the pre-test mean scores of anxiety (P = 0.74) and grief (P = 0.95) did not show significant between-group differences, and the post-test mean scores of anxiety (P < 0.001) and grief (P = 0.004) in the intervention group were significantly less than the control group. Conclusions: Positive ST is effective in significantly reducing anxiety and grief among women with SA. Nurses and psychologists can use positive ST to reduce post-SA psychological complications among afflicted women.