Sight-reading poses persistent challenges for professional musicians, particularly those lacking adept sight-reading skills. Recognizing the practical implications of sight-reading as a facilitator of musical learning, scholarly endeavors have sought to identify the components that influence sight-reading proficiency. The focus on diverse tonal environments has surfaced as a key avenue for unveiling the complexities of tonality-related sight-reading skills. Against this backdrop, the present study delved into the intricate relationship between sight-reading components and tonal characteristics in music, employing performers’ self-assessments of their proficiencies in these domains. The findings revealed that sight-readers exhibit comparable self-assessments of their proficiency in sight-reading, but a significant disparity emerged between tonal and atonal sight-reading. Common predictors—rhythm reading, playing by ear, and performance techniques—emerged as influential factors explaining proficiency in both tonal and atonal sight-reading proficiency. In contrast, the predictors that include knowledge of tonal center, tonal function, and basic music theory were indicative for tonal sight-reading, while music interpretation and complexity of tonality were connected to atonal sight-reading proficiency. The findings highlight the useful integration of sight-reading components within diverse tonal environments, which offers flexibility, practicality, and adaptability in sight-readers’ practice.