The Ifo business climate rose by one point compared to the previous month to 91.8 points, as the Ifo Institute announced on Monday in Munich.
Analysts, on the other hand, had expected a slowdown to 89.0 points on average.
In March, Germany's most important economic barometer collapsed due to Russia's invasion of Ukraine.
"After the initial shock of the Russian attack, the German economy has shown itself to be resilient," commented Ifo President Clemens Fuest.
Sentiment has stabilized at a low level.
The still pessimistic expectations of the companies brightened noticeably, the current situation was rated hardly better.
The business climate improved in industry and among service providers, while it deteriorated in trade and construction.
The current development shows a certain glimmer of hope that the German economy is at least not going into free fall, explained expert Elmar Völker from the Landesbank Baden-Württemberg.
The first war shock seems to have subsided somewhat.
In view of the large number of existing risks, however, it is still too early to speak of the beginning of a trend reversal.
"The course of the Ukraine war remains difficult to predict, including a possible gas supply stop." High inflation is already having a significant impact on the economic outlook, and the repeated corona outbreaks in China are threatening to dampen trade.
"The outlook for the German economy is brightening somewhat," stated Thomas Gitzel, Chief Economist at VP Bank.
"But there can be no question of ease in German companies." The message of the business climate is: It is not quite as bad as feared after the outbreak of the war, but the situation remains tense.
In addition to the war in Ukraine, the international supply chains would be disrupted by China's strict corona countermeasures.
This puts a strain on the industry, while service providers are currently benefiting from fewer corona restrictions in Germany.