The 26-year-old fended off competition from several Premier League stars including Arsenal striker Pierre-Emerick Aubameyang, Manchester United attacker Anthony Martial, reborn Chelsea midfielder Ross Barkley, Manchester City maestro Fernandinho and Brighton teammate Shane Duffy.
Ryan did not concede a single Premier League goal during the month of October, saving all 17 shots he faced against West Ham, Newcastle and Wolverhampton, to help Brighton secure three crucial victories.
Only Manchester United's David De Gea and Burnley's Joe Hart (both 20) faced more shots on target than Ryan did in the previous calender month.
The former Valencia goalkeeper has made 43 stops this season at a save percentage of 73 percent, with only Hart (49) and West Ham's Lukasz Fabianski (45) saving more shots.
Ryan enjoyed a quality debut campaign for Brighton last season, saving 69 percent of shots faced on target as Chris Hughton's men defied relegation predictions to finish 15th.