It looks like prior to WW2 they had some good tanks based on a UK (LT vz.34 Carden Loyd tankettes), and German design (Kolohousenka) . Then the Nazis invaded. After the war they then they produced under license the rather successful T54 T55, and T72.

https://en.m.wikipedia.org/wiki/Tanks_of_Czechoslovakia

Tanks

Kolohousenka LT vz. 34 - ČKD/Praga P-11 light tank. Fifty built for Czechoslovakia.[29]

LT vz. 35 - Škoda S-IIa light tank built for Czechoslovak army. Captured examples used by Germany as Panzer 35(t).[29]

LT vz. 38 - ČKD/Praga TNH light tank built for Czechoslovakia and export. Adopted by German army as Panzer 38(t) and continued in production until 1942.[30]

ST vz. 39 - Prototype medium tank design by ČKD/Praga. Ordered by Czechoslovak army but production plans stopped by German takeover.[31]

AH-IV - Two-man light tank built for export.[32]

F-IV-HE - 1937 prototype three-man amphibious light tank.[32]

Škoda S-IIb/S-II-c/T-21 - Medium tank design rejected by Czechoslovakia in favour of the St vz. 39, but was developed into the 40M Turán I by the Hungarians.[29]

Škoda T-24 - The Škoda T24 is a lightly armoured medium tank designed by the Škoda car company.

T-54/55 - 1,800 T-54s were ordered in 1957 and produced under license between 1958 and 1963. 1,700 T-55s were ordered in 1963 and produced under license between 1964 and 1973.[7] Overall 2,700 T-54s were produced under license between 1957 and 1998 and 8,300 T-55s and T-55As between 1964 and 1983 (T-55A was probably produced since 1968) (most for export). Passed on to successor states.

T-72 - About 1,700 T-72/T-72M/T-72M1 were produced between 1981 and 1990. The Czechoslovak army had 815 T-72 in 1991.

ST-I - Post-war Czechoslovak designation for Jagdpanzer 38 "Hetzer". 249 were in service until being discontinued in the 60s.[33]

[–] Justas@sh.itjust.works 2 points 1 day ago

LT vz. 38 - ČKD/Praga TNH

21 tanks were ordered by Lithuania, but were scheduled to be finished in 1940. The Soviet occupation changed all that, however.