Loosestrife is the common name of a number of different flowering plants. The species belong to two taxonomic genera, Lythrum, within the family Lythraceae, and Lysimachia, within the family Primulaceae.

Lythrum species known as loosestrife include:

• Lythrum californicum (California loosestrife)
• Lythrum curtissii (Curtiss' loosestrife)
• Lythrum flagellare (Florida loosestrife)
• Lythrum hyssopifolia (hyssop loosestrife)
• Lythrum ovalifolium (low loosestrife)
• Lythrum portula (spatulaleaf loosestrife)
• Lythrum salicaria (purple loosestrife)
• Lythrum thymifolia (thymeleaf loosestrife)
• Lythrum tribracteatum (threebract loosestrife)
• Lythrum virgatum (European wand loosestrife)

Lysimachia species known as loosestrife include:

• Lysimachia ciliatum (fringed loosestrife)
• Lysimachia clethroides (gooseneck loosestrife)
• Lysimachia quadrifolia (whorled loosestrife)
• Lysimachia vulgaris (garden or yellow loosestrife)