Athletics will be the eye-catching event in May. The "Bird's Nest" will unveil its mystery in May when the "Good Luck Beijing" China Athletics Open is held there. It will be the first competition to be held in the National Stadium prior to the Olympic Games. Liu Xiang will attend the competition. The detailed calendar is as follows:
| Start Date | End Date | Sport / Discipline | Event | Location | NOC | Qualification |
| 1-May | Badminton | BWF ranking list to be used to determine qualification | ||||
| 1-May | Equestrian | FEI Olympic Riders Ranking -- Eventing used to determine individual entries | ||||
| 1-May | Equestrian | FEI to inform NOCs/NFs of their qualified quota positions (also for ranking list) | ||||
| 2-May | 3-May | Triathon | 2008 Guangzhou ASTC Triathlon Asian Championships | Guangzhou | CHN | |
| 3-May | 4-May | Wrestling | 2nd freestyle qualification tournament, Warsaw (POL) | The first 3 men and the first 2 women in each weight category will qualify. | ||
| 4-May | Triathon | 2008 Richards Bay BG Triathlon World Cup | Richards Bay | RSA | ||
| 4-May | Triathon | 2008 Roatan ITU Triathlon Pan American Cup | Roatan | HON | ||
| 6-May | 11-May | Beach Volleyball (Men) | Prague Open | Prague | CZE | |
| 7-May | Fencing | The FIE forwards the results of the zone-qualifying events | ||||
| 7-May | 11-May | Archery | European CQT, European Outdoor Archery Championships | Vittel | FRA | The first 3 athletes of European Qualification Tournaments will qualify. |
| 8-May | 11-May | Table Tennis | Final World Qualification Tournament for singles | Budapest | HUN | 2 singles places will be allocated to the top 2 players at the World Qualification Tournament |
| 8-May | Football | Confederations to complete preliminary competitions | ||||
| 9-May | 11-May | Canoe/Kayak Flatwater | Olympic Qualification - Asia | Komatsu | JPN | 16 men and 7 women athlete quota places will qualify |
| 9-May | 11-May | Canoe/Kayak Slalom | Olympic Qualification -- Europe | Krakow | POL | 8 men and 2 women athlete quota places will qualify |
| 10-May | 11-May | Triathon | 2008 Lisbon ETU Triathlon European Championships | Lisbon | POR | |
| 10-May | 11-May | Triathon | 2008 Subic Bay ITU Triathlon Asian Cup | Subic Bay | PHI | |
| 10-May | Badminton | BWF notifies Member Associations of qualified players/pairs | ||||
| 10-May | 11-May | Wrestling | 1st Greco-Roman qualification tournament, Cairo (EGY) | The first 4 men and the first 2 women in each weight category will qualify. | ||
| 13-May | 18-May | Beach Volleyball (Women) | Seoul Open | Seoul | KOR | |
| 13-May | 18-May | Beach Volleyball (Men) | Italian Open presented by Abruzzo | Roseto degli Abruzzi | ITA | |
| 15-May | Synchronized Swimming | NFs/NOCs to confirm the participation of their team/duet to FINA | ||||
| 15-May | 18-May | Canoe/Kayak Flatwater | Olympic Qualification -- Europe | Milan | ITA | From 20 to 32 men and from 8 to 14 women athlete quota places will qualify |
| 15-May | 18-May | Canoe/Kayak Flatwater | Olympic Qualification -- America | Montreal | CAN | 16 men and 7 women athlete quota places will qualify |
| 15-May | Weightlifting | Deadline for completion of continental qualification events | ||||
| 17-May | 18-May | Canoe/Kayak Slalom | Olympic Qualification - Asia | Nakorn Nayok | THA | 4 men and 1 women athlete quota places will qualify |
| 17-May | 18-May | Wrestling | 1st qualification tournament for women's wrestling, Edmonton (CAN) | The first 4 men and the first 2 women in each weight category will qualify. | ||
| 17-May | 25-May | Volleyball | Women's Continental Olympic Qualification Tournament | Tokyo | Japan | 1 team |
| 17-May | 25-May | Volleyball | Women's World Olympic Qualification Tournament | Tokyo | Japan | 1 team |
| 18-May | Triathon | 2008 Brno ITU Triathlon European Cup | Brno | CZE | ||
| 18-May | Triathon | 2008 Isla Margarita ITU Triathlon Pan American Cup - PATCO Triathlon South American Championship | Isla Margarita | VEN | ||
| 18-May | Canoe / Kayak | Deadline for completion of Continental Qualification Competitions | ||||
| 18-May | Hockey | FIH confirms qualification to the National Association and NOC | National Associations/NOCs to confirm their participation in the Olympic hockey tournament in writing to FIH | |||
| 20-May | 25-May | Beach Volleyball (Women) | Osaka Open | Osaka | JAN | |
| 20-May | 25-May | Beach Volleyball (Men) | VIP Open | Zagreb | CRO | |
| 21-May | Judo | Continental Unions to confirm to the NFs/NOCs the places allocated | ||||
| 23-May | 24-May | Triathon | 2008 Yicheng ITU Triathlon Asian Cup | Yicheng | CHN | |
| 23-May | 25-May | Volleyball | Men's World Olympic Qualification Tournament | Dusseldorf | GER | 1 team |
| 24-May | 25-May | Triathon | 2008 Serres ETU Duathlon European Championships | Serres | GRE | |
| 24-May | 25-May | Wrestling | 2nd Greco-Roman qualification tournament, Novi Sad (SRB) | The first 3 men and the first 2 women in each weight category will qualify. | ||
| 25-May | Triathon | 2008 Madrid BG Triathlon World Cup | Madrid | ESP | ||
| 25-May | Triathon | 2008 Amakusa ITU Triathlon Asian Cup | Amakusa | JAN | ||
| 26-May | 31-May | Beach Volleyball (Women) | Barcelona Open | Barcelona | ESP | |
| 27-May | 1-Jun | Modern Pentathlon | 2008 World Championships | Budapest | HUN | The top 3 placed athletes qualify |
| 27-May | 1-Jun | Beach Volleyball (Men) | BARCELONA OPEN | Barcelona | ESP | |
| 30-May | 1-Jun | Handball | IHF Men's Qualifying Round | The remaining 6 (men) and 6 (women) teams qualify through IHF Qualifying Events | ||
| 30-May | 1-Jun | Volleyball | Men's World Olympic Qualification Tournament | Espinho | POR | 1 team |
| 31-May | 1-Jun | Swimming | FINA Marathon Swimming Olympic Qualifying | Beijing | CHN | All the remaining seats will be allocated. |
| 31-May | Swimming | NFs/NOCs to confirm to FINA the participation of their qualified relay teams | ||||
| 31-May | Cycling | Establishment of the women's Elite rankings. | 64 women | |||
| 31-May | Cycling - BMX | Establishment of the UCI rankings of the nations which will qualify | 24 Men and 12 Women | |||
| 31-May | Badminton | Member Associations/NOCs confirm to BWF their selection of qualified players/pairs | ||||
| 31-May | Weightlifting | IWF to determine individual qualifications on the basis of the Olympic Qualification Ranking Lists | ||||
| 31-May | Weightlifting | IWF to notify NFs/NOCs on qualification places obtained | ||||
| 31-May | 1-Jun | Wrestling | 2nd qualification tournament for women's wrestling, Happaranda (SWE) | The first 3 men and the first 2 women in each weight category will qualify. | ||
| 31-May | 8-Jun | Volleyball | CONTINENTAL OLYMPIC QUALIFICATION TOURNAMENTS | Tokyo | JPN | 1 team |
| 31-May | 8-Jun | Volleyball | Men's World Olympic Qualification Tournament | Tokyo | JPN | 1 team |
| 31-May | Rowing | Deadline for NOCs to confirm to FISA use of qualification places gained at the 2007 World Championships and Continental Qualification Regattas in Asia, Africa and Latin America | ||||
| 31-May | Equestrian | NOCs to confirm use of qualified quota positions to FEI |