Background: Spine stability or core stability exercises are among the most recommended interventions in low back pain management. It is important to clarify whether physical activity and body adiposity affect lumbar muscle multifidus (LMM) among apparently healthy adults. Objectives: The current study aimed at investigating the effect of physical activity level (PAL) and body adiposity on fatty infiltration of LMM in apparently healthy individuals from an urban African setting. Methods: Fatty infiltration of LMM was visually graded as normal, slight, and severe using diagnostic ultrasound. Validated Hausa and English versions of IPAQ were employed to analyze PAL, and the bioelectrical impedance analysis machine was used to measure some of the body adiposity parameters and weight. Results: A slight fatty infiltration of LMM was observed in 40.3% of 196 participants. Slight fatty infiltration of LMM had a higher prevalence in female subjects (39.2%) than males (34.2%). Only two variables of age (P = 0.032; r = 0.153) and visceral fat (P = 0.0001; r = 0.308) had a relationship with fatty infiltration of LMM. Conclusions: Fatty infiltration of LMM was positively associated with visceral fat and weakly with age among the participants. However, fatty infiltration of LMM had no relationship with the PAL.