Homelessness is rising among public school students in large cities across the US. Using nine years of student-level administrative data, we examine how homelessness affects students' mathematics and attendance outcomes within the Los Angeles Unified School District, including the differential effects of homelessness based on duration and timing of their homeless experiences. Results using inverse probability of treatment weighting find that homeless students score 0.13 SD lower on math assessments and miss 5.8 additional days of school than students who never experience homeless. Results suggest that current homelessness has larger negative impacts on math achievement and attendance than former homelessness, and that transitory homelessness has larger negative impacts than persistent homelessness on the same outcomes.