Gotovina, whom the Spanish police arrested in the night between Wednesday and Thursday in the Canaries, had been at large since 2001 when the UN war crimes tribunal at The Hague indicted him from crimes allegedly committed during the 1995 Operation Storm.
The association expressed support to Gotovina and his family.
It also requested the Croatian authorities and all political factors to take all necessary measures so as to prevent "irreparable historic damage to the present and future generations of Croatian citizens".
Some 200 members of Homeland War associations and residents of the eastern Croatian city of Osijek on Friday expressed support to Gotovina and Branimir Glavas, a powerful local official who earlier this year was ousted from the ruling Croatian Democratic Union and was today called for a police interview.
The participants in the peaceful protest said they organised the rally to pay respect to Croatian generals.
The Association of Disabled Homeland War Veterans (HVIDRA) said today it fully supported general Gotovina, adding that it was convinced he was innocent. HVIDRA said it would organise peaceful protests at noon on Sunday across Croatia to support the general. The association requested the Croatian authorities to provide legal aid and other forms of assistance to general Gotovina and other Croatian ICTY indictees.
Protests will be peaceful, without speeches, and the main rally in support of Gotovina will be organised later, most probably in Zagreb, HVIDRA officials announced.