Summary: As part of a recent effort to summarize research-based knowledge of prospective elementary school teachersâ€™ (PTs) mathematical content knowledge, this paper summarizes research literature on PTsâ€™ knowledge of algebra, focusing on the range of years from 1998 through 2012. The 21 papers included in this summary focus on a broad range of topics within algebra, such as (a) producing, representing, and justifying generalizations; (b) interpreting and using algebraic symbols; (c) solving algebraic word problems; and (d) understanding functions. Looking across this body of research, three themes are identified: (1) PTs generally have strong procedural skills and can make mathematically sound generalizations of many different types of patterns; (2) however, PTs tend to struggle to (a) interpret and effectively use algebraic symbols, even those that they have produced themselves; (b) interpret graphical representations; and (c) make connections between representations; and (3) PTs have limited algebraic problem-solving strategies, often relying, inflexibly, on inefficient and/or incorrect computational methods. Suggestions for future research directions are discussed.