This study aimed to examine the locus of age of acquisition (AoA) and word frequency (WF) effects in Chinese spoken picture naming, using a picture–word interference task. We conducted four experiments manipulating the properties of picture names (AoA in Experiments 1 and 2, while controlling WF; and WF in Experiments 3 and 4, while controlling AoA), and the relations between distractors and targets (semantic or phonological relatedness). Both Experiments 1 and 2 demonstrated AoA effects in picture naming; pictures of early acquired concepts were named faster than those acquired later. There was an interaction between AoA and semantic relatedness, but not between AoA and phonological relatedness, suggesting localisation of AoA effects at the stage of lexical access in picture naming. Experiments 3 and 4 demonstrated WF effects: pictures of high-frequency concepts were named faster than those of low-frequency concepts. WF interacted with both phonological and semantic relatedness, suggesting localisation of WF effects at multiple levels of picture naming, including lexical access and phonological encoding. Our findings show that AoA and WF effects exist in Chinese spoken word production and may arise at related processes of lexical selection.