[4] The team made a number of signings before the 2015 season including Genoveva Añonma who captains the Equatorial Guinea women's national football team,[5] a 2015 NWSL College Draft day trade of the Thorns' 2014 season leading scorer Jessica McDonald for Jodie Taylor of the England women's national football team and leading scorer of the Washington Spirit,[6] and defender Kat Williamson, former Thorns player who had been traded away during the 2014 season.

[14] Due to the national team player callups for the 2015 FIFA Women's World Cup, the league announced that they would be taking a two-week break and shortening the season from 24 to 20 games.

Last updated: September 5, 2015Source: Portland Thorns * – denotes amateur call-ups Note: Flags indicate national team as defined under FIFA eligibility rules; some limited exceptions apply.

Source: Portland Thorns (archived) Win Tie Loss Last updated: September 5, 2015 Source: National Women's Soccer League Pld = Matches played; Pts = Points; W = Matches won; T = Matches tied; L = Matches lost; GF = Goals for; GA = Goals against; GD = Goal difference Source: NWSL Key to positions: FW – Forward, MF – Midfielder, DF – Defender, GK – Goalkeeper On January 14, 2015, the league held its NWSL Player Allocation with Portland receiving six players: returning United States women's national soccer team players Alex Morgan, Rachel Van Hollebeke, and Tobin Heath, returning Canada women's national soccer team player Christine Sinclair, and new Canadian internationals Kaylyn Kyle, and Rhian Wilkinson.

[18] Several Thorns players have been selected to play for their national teams in the 2015 FIFA Women's World Cup in Vancouver, British Columbia, Canada.