The current study investigates DP-internal adjectives in Spanish/English code-switching (CS). Specifically, it analyzes two concomitant phenomena that have been previously investigated; namely, the distributional frequency and placement of adjectives in mixed determiner phrases (DPs). A total of 1680 DPs (477 monolingual Spanish and 1203 Spanish/English DPs), extracted from sociolinguistic interviews with 62 consultants from Northern Belize, were quantitatively examined. This paper is the first of its kind to examine adjectives in the innovative Spanish/English CS variety of Northern Belize, an understudied context where bilingual CS has thrived among younger generations. The distributional and statistical analyses revealed that the avoidance of Spanish attributive adjectives and overt gender marking is a distinguishing characteristic of mixed DPs but not monolingual Spanish DPs, a finding that supports Otheguy and Lapidus’ (2003) adaptive simplification hypothesis. In terms of adjective placement, both the Matrix Language Frame model and the Minimalist approach to CS were able to account for mixed noun-adjective DPs, with the exception of a few cases that could only be predicted by the former model. The present analysis highlights the pivotal role that simplification and convergence play in code-switchers’ optimization of linguistic resources in bi/multilingual discourse.