Brazilian Oliveira stunned Oscar Pistorius by edging out the South African to claim the 200m - T44 title, clocking a winning time of 21.45.
Meanwhile, Weir confirmed his status as the world's best wheelchair racer with victory in the men's 5000m - T54.
In the Swimming pool, Mallory Weggemann clinched victory in the 50m Freestyle - S8, setting a new Paralympic and USA record of 31.13 in the process.
China won two of the four Paralympic Rowing gold medals, with Huang Cheng claiming the men's Single Sculls - ASM1x title. Ukraine's Alla Lysenko won the women's event (ASW1x).
Lou Xiaoxian and Fei Tianming won China's second gold in the men's Mixed Double Sculls - TAMix2x, while Britain's Mixed Coxed Four - LTAMix4+ beat Germany to add the Paralympic title to their world title.
China also dominated the Table Tennis finals today, winning six gold medals and three silvers from 11 finals at the ExCeL Centre.
Feng Panfeng launched the gold rush with a 3-0 victory over the retiring Zlatko Kesler of Serbia.
Great Britain's Equestrian riders won a fifth successive Team title and backed it up with three Individual medals, including a gold for 24-year-old Sophie Christiansen in Grade Ia.
The British team of Christiansen, Lee Pearson, Sophie Wells and Deb Criddle triumphed with a new Paralympic record Team score of 468.817.
It was Pearson's 10th Paralympic gold of a stellar career, putting him one behind British record-holders Baroness Tanni Grey-Thompson and David Roberts.
Egypt's Fatma Omar won her fourth successive Paralympic gold medal with a world-record lift of 143kg in the women's -56kg Powerlifting.
China's Liu Lei also set a new world record with a lift of 226kg to win gold in the -67.5kg division, while Mexico's Amalia Perez won the women's -60kg title.
Great Britain's Mel Clarke and defending champion Danielle Brown both came from behind to reach the semi-finals of the women's Individual Compound - Open Archery event.
Three Russians claimed semi-final places in the Individual Recurve - Standing, while reigning women's champion Lee Hwa Sook from Republic of Korea also progressed after a slow start.
Spain maintained their unbeaten start to the 5-a-side Football competition with a 2-0 win against Iran, while Argentina drew 0-0 with Great Britain.
In Pool B, defending champions Brazil turned on the style to beat Turkey 4-0 while China and France played out a goalless draw.
Defending Mixed Team - BC1-2 Boccia champions Great Britain opened their campaign with pool victories over Argentina and Portugal, while Republic of Korea, ranked world number one, overcame Ireland and Brazil.
USA duo Jen French and JP Creignou sailed into medal contention with two race wins in the 2-person Keelboat (SKUD18), while Australia have replaced Great Britain on top of the overall standings.
Korea's Kang Juyoung won gold in the Mixed R4-10m Air Rifle Standing-SH2 with a Paralympic final record of 705.5 points
In the men's Sitting Volleyball, China and Great Britain both recorded 3-0 pool stage victories over Rwanda and Morocco respectively.
Patrick Anderson's triple double led Canada to a hard-fought 73-66 Wheelchair Basketball win over Germany that sends them clear at the top of Group B with a 4-0 record. Japan are still alive in the group after beating Colombia 63-49.
The Canadian women's team beat Brazil 65-51 to eliminate the South Americans and send Great Britain through.
Defending men's Wheelchair Tennis champion Shingo Kunieda continued his progression with another 6-0 6-0 victory in the round of 32, this time over Zimbabwe's Nyasha Mharakurwa in just 36 minutes.
Peter Norfolk, the reigning quad singles champion, breezed into the quarter-finals with a 6-0 6-0 victory over Mitsuteru Moroishi.