The British Gurkha Welfare Society said it intends to appeal
Retired Gurkhas have lost a High Court test case battle with the Ministry of Defence over pension rights.
The British Gurkha Welfare Society was seeking a judicial review against a decision to limit the pensions paid to those who left the service before 1997.
The veterans can get a third of the monthly amount of UK-based soldiers.
The court agreed it was lawful to apply pension improvements only to those in the Gurkhas when the regiment moved to Britain from Hong Kong.
An MoD spokesperson welcomed the ruling, and said: "We have always sought to treat ex-Gurkhas fairly.
"The Gurkhas are amongst the best and the bravest and we will continue to honour and reward their commitment and sacrifice under our existing arrangements."
The changes to pension rules in 2007 gave serving Gurkha soldiers equal pension rights with their UK counterparts.
But the British Gurkha Welfare Society said about 25,000 men who retired before 1 July 1997 were denied the opportunity to transfer into UK armed forces pension schemes.
After a high profile campaign last year headed by the actress Joanna Lumley, all retired Gurkhas now have the right to settle in the UK.
Lawyers claimed the failure to give them equal pension rights amounted to unlawful discrimination on grounds of nationality and age and was in breach of the Human Rights Act and EU discrimination laws.
Their pension scheme paid lower benefits based on the cost of living in Nepal, the homeland to which they traditionally retired.
Two soldiers named as lead claimants in the legal challenge, Corporal Surbarna Adhikari, from Reading, and Major Tikendra Dewan, from Farnborough, had been claiming damages against the MoD for alleged unequal treatment.
Mr Adhikari, who served 15 years before his discharge in February 1997, is ineligible to transfer any pensionable years to the armed forces schemes.
Mr Dewan, who served almost 31 years before being discharged in July 2002, is able to transfer part of his pension, but his lawyers say the 26 of those years that fell before 1997 will earn him about a third of what a UK soldier receives.
The MoD, however, maintains that Gurkha pensions can be paid over a longer period and amount to the same final level as the UK schemes.
Mr Justice Burnett spoke of the "high regard" the British people had for the Gurkhas.
But he ruled the MoD had not acted unlawfully and rejected all the grounds of the challenge. He said the Gurkhas had not established that the MoD failed to comply with obligations, and ordered them to pay its legal costs.
'More to do'
The British Gurkha Welfare Society said it would be seeking leave to appeal against the decision.
Gurkhas won the right to settle in the UK after a high profile campaign
The society's general secretary, Chhatra Rai, suggested improved pensions rights could save the government money as Gurkhas would be less inclined to move to the UK and there would be less pressure on the welfare system.
He added: "Notwithstanding the savings that could be made by increasing the future monthly pension payments for Gurkhas, this is above all a moral issue as the majority of Gurkha veterans in this group are now becoming increasingly old and fragile."
Labour MP George Howarth, who sponsored a parliamentary motion supporting an improved Gurkha pension, said: "The fact that this small but significant group of veterans are still discriminated against shows that there is still more to do to ensure that the Gurkhas are treated properly and fairly."