The general consensus in the field is that when the home language is different from the language of instruction in school then children’s literacy attainments could slow down. In this 26‐year review of the literature on children’s literacy attainments in low‐ to middle‐income countries, 40 correlational, ethnographic and intervention studies provide the data. We test the ‘home language advantage’ hypothesis where we expect children who speak the same language at home and school to show better literacy learning. We also examine other attributes in the home language and literacy environment (HLLE). Among the multivariate studies, trends differ across countries, age and grade levels, and child measures. Rather than a universal home language advantage, the evidence shows that home language advantage is context‐sensitive. The correlational and ethnographic evidence point to a multiple risk factors model of home and school language disconnection; and the ethnographic and intervention studies provide complementary evidence of both feelings of unease, disempowerment and wish to help among family members, and increased confidence following guided support. Possible underlying mechanisms are examined through parallel synthesis of evidence from multiple research methods on three HLLE dimensions—books‐at‐home, home tutoring and adult literacy practices. The data partially corroborate findings from high‐income countries (e.g. home environments impact literacy development, responsive parenting is present across families) but also bring focus on context‐specific realities. Neither low‐income nor low‐print environments are uniform constraints because communities differ and some homes use available resources more efficiently than others.