We report measurements by the T2K experiment of the parameters
θ
23
and
Δ
m
2
32
, which govern the disappearance of muon neutrinos and antineutrinos in the three-flavor PMNS neutrino oscillation model at T2K’s neutrino energy and propagation distance. Utilizing the ability of the experiment to run with either a mainly neutrino or a mainly antineutrino beam, muon-like events from each beam mode are used to measure these parameters separately for neutrino and antineutrino oscillations. Data taken from
1.49
×
10
21
protons on target (POT) in neutrino mode and
1.64
×
10
21
POT in antineutrino mode are used. The best-fit values obtained by T2K were
sin
2
(
θ
23
)
=
0.51
+
0.06
−
0.07
(
0.43
+
0.21
−
0.05
)
and
Δ
m
2
32
=
2.47
+
0.08
−
0.09
(
2.50
+
0.18
−
0.13
)
×
10
−
3
 
 
eV
2
/
c
4
for neutrinos (antineutrinos). No significant differences between the values of the parameters describing the disappearance of muon neutrinos and antineutrinos were observed. An analysis using an effective two-flavor neutrino oscillation model where the sine of the mixing angle is allowed to take nonphysical values larger than 1 is also performed to check the consistency of our data with the three-flavor model. Our data were found to be consistent with a physical value for the mixing angle.