The present study was carried out with the aim of Investigation of academic procrastination prevalence and its relationship with academic self-regulation and achievement motivation among high-school students in Tehran city. The sample included 624 high school students (312 Boys & 312 Girls) from different areas and regions that selected using random cluster-multistage sampling method. Procrastination Assessment Scale-Student (Solomon & Rothblum, 1984), Self-Regulated Learning Strategies questionnaire (Zimmerman & Pons, 1982) and Achievement motivation test (Hermans, 1970) were used in this study. Data were analyzed in two parts, descriptive and inferential statistics. The results of academic procrastination prevalence using descriptive statistic showed that over half of students nearly always or always procrastinate. Also, results showed that boys and girls procrastinate with the same rate, in general. And boys more than girls procrastinate only on preparing academic tasks. The result of regression analysis also showed that academic self-regulation and achievement motivation predict academic procrastination significantly.