Five new species of Fergusobia are described. Fergusobia janetae Davies n. sp. is characterized by the combination of an arcuate to straight, spindle-shaped parthenogenetic female with a relatively small oesophageal gland, an extensile uterus and a conoid tail, an arcuate infective female with a bluntly rounded tail tip, and a C-shaped male with an arcuate to angular spicule and bursa arising at more than 90% of body length. Fergusobia robustae Davies n. sp. is characterized by the combination of a small, C-shaped parthenogenetic female with a short cylindroid tail with a broadly rounded tip; an arcuate to C-shaped, relatively broad, infective female with a tail tip that is almost hemispherical; and an arcuate male with a strong angular spicule and a bursa arising at 30–40% of body length. Fergusobia pruinosae Davies n. sp. is characterized by the combination of a medium sized, open C-shaped, parthenogenetic female in which the cuticle does not swell upon fixation, with a strongly sclerotised stylet, with a more or less narrowly conoid tail with a bluntly or broadly rounded tip; infective female that is arcuate to J-shaped with a notched tail tip; and open C-shaped males with stout, angular spicules and bursa arising near the secretory/excretory pore. Fergusobia pauciflorae Davies n. sp. is characterized by the combination of a medium sized, arcuate, parthenogenetic female with a small stylet, and a conoid tail with a bluntly rounded tip; a small, open C to J-shaped infective female with a broadly rounded to almost hemispherical tail tip; and straight to arcuate males with stout, angular spicules and bursa at ~70% of body length anterior to the cloaca. Fergusobia obliquae Davies n. sp. has a relatively broad, arcuate, parthenogenetic female having a small but strongly sclerotised stylet, and a short conoid tail with a bluntly rounded tip; an arcuate, infective female with an almost hemispherical tail tip; and C-shaped males with arcuate to angular (not heavily sclerotised) spicules and bursa arising 50–80% of body length anterior to tail. Sequencing of the 18S and 28S rDNA domains for F. janetae n. sp. and of mitochondrial DNA cytochrome oxidase subunit I (mtCOI) for F. pauciflorae n. sp. confirm that they are distinct species.