Mother-infant bed-sharing has been a common practice for centuries. Understanding the reasons parents choose to bed-share can help tailor safe sleep education. The purpose of this article was to systematically review the international literature on: (1) reasons parents bed-share, (2) the cultural context of bed-sharing, and (3) implications for interventions and future research. The search occurred August-September 2013 via PubMed, CINAHL, and Psyc INFO using the terms: "infant," "sleep," "bed shar*," "co sleep*," "sleep location," "sleep practices," and "sleep arrangements," alone or in combination. Google Scholar was searched using: "bed share," "bed sharing," "co sleep," and "co sleeping." Inclusion criteria were: (1) referenced bed-sharing with infants 12 months or younger; (2) provided reasons for bed-sharing; and (3) published between 1990 and 2013. Studies were excluded if they focused on disorders such as epilepsy, breathing disorders, or among multi-gestational infants. Narrative synthesis was used to summarize findings. Thirty-four studies met inclusion criteria. The main themes around bed-sharing based on this synthesis included: (1) breastfeeding, (2) comforting, (3) better/more sleep, (4) monitoring, (5) bonding/attachment, (6) environmental, (7) crying, (8) tradition, (9) disagree with danger, and (10) maternal instinct. Findings suggest that future research should examine parents' decision-making process on infant sleep location, including how they weigh personal reasons and sources of advice. Public health interventions should incorporate the particular reasons of the population they are targeting. Clinicians should discuss infant sleep environment with each family, along with their motivations for choosing this environment, and work within that framework to address the safety of the sleep environment.