Background: Multitasking while reading is a commonplace activity. Many studies have been conducted examining the effect of multitasking on reading comprehension and times. The purpose of this meta-analysis is to consolidate the empirical findings on reading comprehension and times in order to understand the overall effect of multitasking on reading. Characteristics of the reading situation, comprehension assessment and the secondary task were examined to determine if they varied the effect of multitasking. Methods: A systematic search of studies on multitasking and reading was conducted. Only studies that used random assignment and had participants reading independently were included. This screening yielded 22 independent studies (20 reports) that met inclusion criteria, with 20 studies on reading comprehension and 9 studies on reading times. Most of the studies involved adults reading expository texts. Results: Based on robust variance estimation analyses, multitasking had a negative effect on reading comprehension (g = -0.28, p = 0.002). The effect was similar after outliers were removed (g = -0.26, p = 0.001). Based on moderator analyses, this negative effect may only occur when time was limited because the reading pace was controlled by the experimenter (g = -0.54, p < 0.001) as there was not a reliable effect when reading was self-paced (g = -0.14, p = 0.10). Multitasking during reading lead to longer reading times (g = 0.52, p < 0.001). Conclusions: Multitasking during reading is detrimental to reading comprehension when time is limited. When readers control their own pace of reading, multitasking lengthens the time for the reading task. Therefore, multitasking while reading is less efficient than focusing attention on the primary task of reading.