Employee stock options (ESO or ESOPs) is a label that refers to compensation contracts between an employer and an employee that carries some characteristics of financial options.

Employee stock options are commonly viewed as an internal agreement providing the possibility to participate in the share capital of a company, granted by the company to an employee as part of the employee's remuneration package. Regulators and economists have since specified that ESOs are compensation contracts.

These nonstandard contracts exist between employee and employer, whereby the employer has the liability of delivering a certain number of shares of the employer stock, when and if the employee stock options are exercised by the employee. The contract length varies, and often carries terms that may change depending on the employer and the current employment status of the employee. In the United States, the terms are detailed within an employer's "Stock Option Agreement for Incentive Equity Plan". Essentially, this is an agreement which grants the employee eligibility to purchase a limited amount of stock at a predetermined price. The resulting shares that are granted are typically restricted stock. There is no obligation for the employee to exercise the option, in which case the option will lapse.

AICPA's Financial Reporting Alert describes these contracts as amounting to a "short" position in the employer's equity, unless the contract is tied to some other attribute of the employer's balance sheet. To the extent the employer's position can be modeled as a type of option, it is most often modeled as a "short position in a call". From the employee's point of view, the compensation contract provides a conditional right to buy the equity of the employer and when modeled as an option, the employee's perspective is that of a "long position in a call option".

Many companies use employee stock options plans to retain, reward, and attract employees, the objective being to give employees an incentive to behave in ways that will boost the company's stock price. The employee could exercise the option, pay the exercise price and would be issued with ordinary shares in the company. As a result, the employee would experience a direct financial benefit of the difference between the market and the exercise prices.

Stock options are also used as golden handcuffs if their value has increased drastically. An employee leaving the company would also effectively be leaving behind a large amount of potential cash, subject to restrictions as defined by the company. These restrictions, such as vesting and non-transferring, attempt to align the holder's interest with those of the business shareholders.

Another substantial reason that companies issue employee stock options as compensation is to preserve and generate cash flow. The cash flow comes when the company issues new shares and receives the exercise price and receives a tax deduction equal to the "intrinsic value" of the ESOs when exercised.

Employee stock options are offered differently based on position and role at the company, as determined by the company. Management typically receives the most as part of their executive compensation package. ESOs may also be offered to non-executive level staff, especially by businesses that are not yet profitable, insofar as they may have few other means of compensation. Alternatively, employee-type stock options can be offered to non-employees: suppliers, consultants, lawyers and promoters for services rendered.