Protection of greenhouse-grown horticultural crops, including ornamentals and vegetables, from damage caused by insect pests involves implementing strategies such as insecticidal and/or biological control. However, cultural control may also mitigate plant damage caused by insect pests, as well as plant diseases including fungi and bacteria. An important cultural control is sanitation. Herein, we review the use and potential impact of sanitation practices as a part of an integrated pest management program for greenhouse production. These include removing weeds from inside and around the greenhouse perimeter, disposing of plant and growing medium debris from inside the greenhouse, and managing algae within the greenhouse. Weeds serve as alternate hosts for insects, such as aphids (Aphididae), whiteflies (Aleyrodidae), and thrips (Thripidae), that can spread plant viruses among greenhouse-grown horticultural crops. Sanitation practices that may reduce problems with weeds include installing geotextile fabric barriers underneath benches and on walkways, hand removal, mowing around greenhouse perimeters, and/or applying herbicides. Plant and growing medium debris serve as sources of insect pests, such as whiteflies, thrips, and fungus gnats (Sciaridae). Therefore, removal of plant and growing medium debris from within greenhouses and/or placement into refuse containers with tight-sealing lids before disposal may reduce problems with insect pests. Algae provides a habitat for fungus gnats and shore flies (Ephydridae) to breed. Overwatering and overfertilizing plants contributes to algae growth. Applying disinfectants or algaecides may mitigate problems with algae accumulating in greenhouses. In addition to reducing insect pest problems, sanitation practices may help reduce inputs from insecticide applications.