This paper informs on the double side of earnings management, that is, when earnings management is considered healthy (efficient) or unhealthy (opportunistic). Earnings management is part of the contract cost that either increases or decreases agency cost. Earnings management also provides a positive or negative impact to firm value and shareholders' wealth. Efficient earnings management is said to maximise firm value and shareholders' wealth. Opportunistic earnings management is known to maximise managers' private benefits at the expense of shareholders, and this eventually affects firm value. Firm performance measurement, either accounting or market-based measurement, can be applied to determine the type of earnings management (efficient or opportunistic). This paper provides valuable information for business and academic players on insights into earnings management and the recognition of the double side of earnings management through firm performance that possibly gives impact on agency cost and continuous survival of firms.