Behavioral interventions to improve cognitive function in older adults are widespread and can vary from theater classes to cognitive training programs. However, the effectiveness in maintaining different cognitive domains varies greatly both across and within intervention types. To date, no systematic reviews have synthesized findings across more than a few types of interventions (e.g., cognitive vs. exercise). This systematic review examined 11 types of behavioral interventions and the respective transfer to 19 cognitive domains, as well as transfer to everyday function. Study inclusion criteria were: peer-reviewed articles in English, samples of healthy adults aged 65 and older, and randomized controlled trials of behavioral interventions with reported cognitive outcomes. The 2017 search yielded 75 eligible articles comprising cognitive training, exercise training, combination interventions, cognitively-stimulating activities, and action video games. In general, process- (n = 26) and strategy-based (n = 16) cognitive training improved the trained domains but had weak transfer to non-trained domains. Aerobic training (n = 13) most consistently improved executive function, and strength/resistance (n = 8) and aerobic/resistance combination training (n = 6) most consistently improved cognitive inhibition and visual working memory. Combination interventions (n = 15 nonfactorial, n = 3 factorial) showed promise in improving verbal delayed recall and executive function. Few studies examined cognitively-stimulating activities or action video games, leaving inconclusive results about their effect on cognitive function. Few studies examined everyday function (n = 9), however, process- and strategy-based training demonstrated notable long-term transfer. Recommendations for future research and practice are highlighted.