This study aimed to examine the effects of an advance care planning (ACP) group which was developed by social workers in Hong Kong for older adults. A quasi‐experimental study was conducted. Participants were recruited from 14 residential care homes. The ACP intervention group included 59 participants for analyses, and the control group 58. Three major outcomes were measured at two time points: (a) Quality‐of‐life concerns, (b) End‐of‐life preference and (c) Advance directive (AD)‐related outcomes (awareness of AD, AD completion, willingness to complete AD and communication with family members about AD). Findings indicate that the ACP group enhanced participants’ awareness of AD compared with the control group. Participants were also more willing to complete AD, and more participants communicated with family members about AD after participating in the ACP group. No significant difference was found in other outcomes. This study demonstrates the efforts of social workers in promoting ACP in Hong Kong and the effectiveness of an ACP group for enhancing older adults’ awareness of AD. Findings support the role of social workers in promoting ACP for deprived groups, like frail older adults. The ACP group could be considered a first step in enhancing older adults’ awareness of and willingness to discuss end‐of‐life issues. Further follow‐up is required to develop individualised ACP for older adults.