The independent report found there was no single direct cause for the incident at the Janefield Street entrance on 2 September last year and that a number of individual factors came together to contribute towards what happened.
One person was taken to hospital after falling from a wall. Four others were treated by first-aiders at the scene following the crush at the first Old Firm game of the season.
Celtic FC ordered sports event safety management consultants Fairhurst to carry out an independent review into the incident.
The Fairhurst review said contributory factors it identified “acted collectively to present a unique set of circumstances on the 2nd September 2018, which had not occurred previously at Celtic Park”.
They included segregation arrangements and the balance of supporter attendance numbers at the match, which was attended by 56,294 supporters.
Of the crowd, 54,344 were home supporters and 796 away supporters, with the balance being hospitality guests.
This was very different to previous fixtures between the two clubs when around 7,000 away supporters attended.
Other contributory factors included a “constrained window” for supporters attending the match to arrive due to the combined effect of the kick-off time, limited public transport and the closure of the railway station closest to the stadium.
The high volume of home supporters arriving and the impact of this on the North Stand underpass and the way contingency plans operated also contributed to the incident.
A Celtic FC spokesman said: “The safety and welfare of supporters visiting Celtic Park will always be our priority and it was therefore essential that a comprehensive and independent review was undertaken.
“We would like to thank Fairhurst for their rigorous work and to thank our supporters and the wide range of agencies who have contributed to the review.
“We regret the events which took place and we will continue to work with Fairhurst in connection with their recommendations, building on our existing good practices, to ensure that Celtic Park continues to be a safe place to visit.”
The review found that communication with supporters during the progress of the incident could have been improved, with stewards and police officers not obviously visible to supporters due to the density of the crowd.
It said a “significant factor in the positive resolution of the incident was the behaviour and mutual concern displayed by those supporters who were involved in the incident”.
Supporters were also invited to contribute to the study, with more than 490 responding.
The review found planning arrangements for the match were in line with those expected for a high profile fixture.
Fairhurst said it has carried out a comprehensive analysis of events on 2 September and has made 29 recommendations.
A spokesman for the firm said: “We have already assisted Celtic with the implementation of our interim recommendations.
“Fairhurst has worked together with Celtic and Police Scotland to incorporate our recommendations into the planning for the match on 31 March 2019 and we will be in attendance at the match to observe the operation of the safety arrangements.”
Chief Superintendent Brian McInulty said: “Police Scotland has been pleased to engage with Fairhurst during their review that was commissioned by Celtic Football Club.
“The safety of spectators attending football matches is a matter for the home clubs and we work with them very closely to support their planning.
“The findings and recommendations from the review were made available to us and they will be implemented as part of our match planning.”