The exact toll from Friday's assault in the northern province of Balkh remains unclear, with some local officials putting the number of dead as high as 130.
The assault, the deadliest-ever by the Taliban on a military base, underscores their growing strength more than 15 years after they were ousted from power.
Flags flew at half-mast throughout the country and special prayers were said for the dead.
The defence ministry gave a figure of at least 100 soldiers killed or wounded. It ignored media calls for a complete breakdown of casualties following the five-hour attack near the provincial capital of Mazar-i-Sharif.
But local officials including, Mohammad Ibrahim Khairandish the head of the provincial council, put the death toll as high as 130 and said about 60 were wounded.
Ten gunmen dressed in soldiers' uniforms and armed with suicide vests entered the base in army trucks and opened fire at unarmed troops at close range in the base's mosque and dining hall.
Ordinary Afghans vented their anger at the government for its inability to counter a series of brazen Taliban assaults, including a raid on the country's largest military hospital in Kabul in March that left dozens dead.
"The best way to honour them is to fire and punish those who failed to do their jobs and/or cooperated with the enemy. Some leaders must go!" said another user on Twitter.
Many called for the resignation of Defence Minister Abdullah Habibi and the commander of the 209th Corps stationed at the base.
"This was no act of desperation. The Taliban infiltrated an Afghan military base. That's a major sign of strength," tweeted Washington-based analyst Michael Kugelman.
A military source at the base indicated the assault was an insider attack, and the terrorists were 'young recruits who had come for training'.
Afghan troops and police, beset by killings and desertions, have been struggling to beat back terrorists since US-led NATO troops ended their combat mission in December 2014.
Afghan security force casualties soared by 35 percent in 2016, with 6,800 soldiers and police killed, according to US watchdog SIGAR.