Is a stop-limit sell order executed purely on a first come first served basis?

External question — Personal Finance Stack Exchange Author: S.O.S Original post: https://money.stackexchange.com/questions/111718 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. The difference between a stop-limit order and a stop or limit order is explained very eloquently in this response : Selling is the same, but the directions are opposite. Suppose the stock in the example above has a current price of $46 and you put in a stop-limit sell with a stop price of $41 and a limit of $40. When the stock drops below $41, a limit sell is placed that will sell your stock for at least $40 if possible. If the stock drops below $40 before your limit order can be filled (e.g. because there are many other sellers front-running you), then your limit order is not filled until the price comes back to $40. Suppose 'ABC' stock is currently trading at $46 and I place a stop-limit order with stop = $42 and limit = $40 . I would expect my sell order to execute somewhere between $40 - $42. If the stock does not reach $42, my trade will not be executed. If the stock hits $42, what determines whose trade gets executed first? Is it executed on a first come first served basis? In other words, if I submitted my stop-limit order on July 1st and Mr. Smith submitted the identical stop-limit order on July 15th, is my order guaranteed to execute before Mr. Smith? Can I be confident that if I was the first to submit a stop-limit order within a certain range, it is (virtually) impossible for me to wake up the next day and see the stock price well below my stop-limit order price (as long as someone wants to buy in range of $40 - $42)? Is there any flaw in this approach?