Current attention to increasing access to family planning has increased focus on ensuring that policy, programming and practice are “evidence-based.” Given the rich history of research in the family planning field, this paper set out to answer when, what types and how evidence is used in decision-making related to family planning. Views of what constitutes evidence need to be more aligned, with researchers understanding that “evidence-based” does not only mean “research evidence-based” to decision-makers and with decision-makers understanding the value of robust research evidence among other evidence they consider when making decisions. Decision-makers appreciate research but it is only one factor they take into consideration – and may not be the most influential factor in their decision-making. Research findings tend to be filtered through decision-makers’ values and beliefs in addition to political, economic and social considerations. Examples from family planning reinforce the persistence of other factors affecting decision-making. A number of promising interventions exist to increase how research evidence, vis a vis other factors, can inform decision-making. Expecting policy or program change from single studies is mostly unrealistic, but examples from decades of family planning programming shown in this paper illustrate the incremental influence of evidence from research on family planning policies and programs.