Background: Immediate implant placement has become increasingly prevalent in clinical practice, and accurate assessment of placement quality is crucial to ensure successful outcomes. Bone-to-implant contact (BIC) is one of the critical determinants of primary stability following implantation. However, its correlation to the implant stability quotient (ISQ) is uncertain. This study aims to determine the relationship between ISQ measurements and BIC in immediately placed implants. Materials and Methods: An atraumatic extraction followed by immediate implant placements were performed on 33 teeth in seven human cadaver heads. The implant ISQ values were measured in four directions: buccal, lingual, mesial, and distal. The cadaver heads were imaged using cone-beam computed tomography (CBCT) to determine the linear BICs in the corresponding directions. Results: Among the twenty-eight implants analyzed, no correlations were observed between directional BICs and the corresponding ISQ values. ISQ measurements did not significantly differ between maxillary and mandibular implants, nor among different anatomical locations. Additionally, when solid contact was present at the implant shoulder, the ISQ values remained stable despite the absence of apical BIC. Conclusion: ISQ values alone appear to be poor predictors of BIC in immediately placed implants. Therefore, ISQ measurements should be interpreted alongside other assessment methods to more accurately evaluate implant stability.