This What Works Clearinghouse (WWC) topic report addresses reading interventions for students in grades K-3, including core reading curricula, programs, or products to be used as supplements to other reading instruction, programs that focus on staff development, and literacy software. The WWC review on beginning reading focuses on programs intended to increase skills in alphabetics, reading fluency, comprehension, or general reading achievement. Twenty-four programs met the WWC evidence screens. In examining the four outcome domains for the 24 interventions, ten interventions had positive effects or potentially positive in all the outcome domains addressed in their studies; eleven interventions had a combination of positive or potentially positive effects in one or two domains while having mixed, negative, or no discernible effects in other domains; and three had only mixed effects or no discernible effects across domains. A table shows the effectiveness ratings for the 24 beginning reading programs in the four outcome domains (alphabetics, reading fluency, comprehension, or general reading achievement). (Contains 2 tables, 3 figures, and 4 footnotes.)