Systems and methods for facilitating payment service-based guest checkout with a merchant are disclosed. According to one embodiment, a method for facilitating payment service-based guest checkout with a merchant may include: (1) receiving, from a merchant's application or website, a redirect of an online interaction between the merchant and a customer; (2) retrieving, from an issuer payment service, wallet information comprising a plurality of payment options for the customer; (3) receiving a selection of one of the payment options; (4) communicating the selection of the payment option to the payment service for the issuer. The issuer payment service provides a session identifier to the merchant application website, the merchant application or website provides transaction information and the session identifier to a merchant payment host, the merchant payment host retrieves the selected payment option from the issuer payment service and conducts the transaction using the selected payment option.