| 2003 WTA Tier I Series | |
| Duration: | January 27 – October 29 |
| Edition: | 14th |
| Tournaments: | 9 |
| Most Tournament Titles: | Justine Henin (4) |
| Most Tournament Finals: | Justine Henin (4) |
| Previous: | 2002 |
| Next: | 2004 |
See main article: article and 2003 WTA Tour.
The WTA Tier I events are part of the elite tour for professional women's tennis organised by the WTA called the WTA Tour.[1]
| Tournament | Country | Location | Surface | Date | Prize money[2] | |
|---|---|---|---|---|---|---|
| Toray Pan Pacific Open[3] | Japan | Tokyo | Carpet (i) | Jan 27 – Feb 2 | $1,300,000 | |
| Pacific Life Open | United States | Indian Wells | Hard | Mar 3 – 16 | $2,100,000 | |
| NASDAQ-100 Open | United States | Key Biscayne | Hard | Mar 17 – 30 | $2,960,000 | |
| Family Circle Cup | United States | Charleston | Clay (green) | Apr 7 – 13 | $1,300,000 | |
| MasterCard German Open[4] | Germany | Berlin | Clay | May 5 – 11 | $1,224,000 | |
| Telecom Italia Masters[5] | Italy | Rome | Clay | May 12 – 18 | $1,300,000 | |
| Rogers AT&T Cup | Canada | Toronto | Hard | Aug 11 – 17 | $1,325,000 | |
| Ladies Kremlin Cup | Russia | Moscow | Carpet (i) | Sep 29 – Oct 5 | $1,300,000 | |
| Swisscom Challenge | Switzerland | Zürich | Hard (i) | Oct 13 – 19 | $1,300,000 |