The recent rise in the use and misuse of psychoactive substances such as antipsychotic drugs, particularly haloperidol and promethazine, has become a source of scientific concern. This study investigated the effects of chronic exposure to separate and combined administration of haloperidol and promethazine on memory and spatial learning behaviour in albino rats. Twenty-four (24) male albino rats weighing 180–200 g were randomly assigned into four experimental groups: haloperidol, promethazine, combined haloperidol and promethazine, and a control group, with six rats per group. The animals received daily oral doses of haloperidol (1 mg/kg) and promethazine (1.1 mg/kg) for 28 consecutive days and were assessed on the Y-maze task for spatial learning and memory performance throughout the experiment. Data were analysed using randomized block ANOVA. Results showed that promethazine did not significantly affect spatial learning and memory, F(1, 332) = 0.21, p > 0.05, η² = 0.00. Haloperidol, however, had a significant effect on learning, F(1, 332) = 4.89, p < 0.001, η² = 0.02. Combined treatment of haloperidol and promethazine produced no significant effect on learning, F(1, 332) = 0.766, p > 0.05, η² = 0.00. Mean learning times revealed that the control group averaged 49.45 s, while the haloperidol group recorded the fastest learning (34.37 s), followed by the combined treatment group (41.25 s) and promethazine group (52.29 s). It was concluded that chronic exposure to haloperidol and promethazine has potential implications for exploratory learning and memory processes, suggesting possible risks of cognitive deficits associated with long-term use.